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abstract

title stringlengths 3 252	abstract stringlengths 13 2.77k	text stringlengths 187 3k
Exclusive Hadronic B Decays to Charm and Charmonium Final States	We have fully reconstructed decays of both B0 and B- Mesons into final states containing either D, D, D*, Psi, Psi', or Chi_{c1} mesons. This allows us to obtain new results on many physics topics including branching ratios, tests of the factorization hypothesis, color suppression, resonant substructure, and the B- - B0 mass difference.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Exclusive Hadronic B Decays to Charm and Charmonium Final States ### Response: We have fully reconstructed decays of both B0 and B- Mesons into final states containing either D, D, D*, Psi, Psi', or Chi_{c1} mesons. This allows us to obtain new results on many physics topics including branching ratios, tests of the factorization hypothesis, color suppression, resonant substructure, and the B- - B0 mass difference.
Observation of a New Charmed Strange Meson	Using the CLEO-II detector, we have obtained evidence for a new meson decaying to $D^0 K^+$. Its mass is $2573.2^{+1.7}_{-1.6}\pm 0.8\pm 0.5$ {}~MeV/$c^2$ and its width is $16^{+5}_{-4}\pm 3$~MeV/$c^2$. Although we do not establish its spin and parity, the new meson is consistent with predictions for an $L=1$, $S=1$, $J_P=2^+$ charmed strange state.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Observation of a New Charmed Strange Meson ### Response: Using the CLEO-II detector, we have obtained evidence for a new meson decaying to $D^0 K^+$. Its mass is $2573.2^{+1.7}_{-1.6}\pm 0.8\pm 0.5$ {}~MeV/$c^2$ and its width is $16^{+5}_{-4}\pm 3$~MeV/$c^2$. Although we do not establish its spin and parity, the new meson is consistent with predictions for an $L=1$, $S=1$, $J_P=2^+$ charmed strange state.
Study of the Decay $Λ_c \to Λl^+ ν_{l}	Using the CLEO II detector at CESR, we observe 500 $\Lambda l^+$ pairs consistent with the semileptonic decay $\Lambda_c \to \Lambda l^+ \nu_{l}$. We measure $\sigma (e^+ e^- \to \Lambda_c X) \dot {cal B}(\Lambda_c^+ \to \Lambda l \nu_{l}) =4.77 \pm 0.25 \pm 0.66 $pb. Combining with the charm semileptonic width and the lifetime of the $\Lambda_c$, we also obtain ${\cal B}(\Lambda_c \to p K^- \pi^+)$. We find no evidence for $\Lambda l^+ \nu_{l}$ final states in which there are additional $\Lambda_c^+$ decay products. We measure the decay asymmetry parameter of $\Lambda_c \to \Lambda l^+ \nu_{l}$ to be $\alpha_{\Lambda_c} =-0.89\pm{^{0.17}_{0.11}}\pm{^{0.09}_{0.06}}.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Study of the Decay $Λ_c \to Λl^+ ν_{l} ### Response: Using the CLEO II detector at CESR, we observe 500 $\Lambda l^+$ pairs consistent with the semileptonic decay $\Lambda_c \to \Lambda l^+ \nu_{l}$. We measure $\sigma (e^+ e^- \to \Lambda_c X) \dot {cal B}(\Lambda_c^+ \to \Lambda l \nu_{l}) =4.77 \pm 0.25 \pm 0.66 $pb. Combining with the charm semileptonic width and the lifetime of the $\Lambda_c$, we also obtain ${\cal B}(\Lambda_c \to p K^- \pi^+)$. We find no evidence for $\Lambda l^+ \nu_{l}$ final states in which there are additional $\Lambda_c^+$ decay products. We measure the decay asymmetry parameter of $\Lambda_c \to \Lambda l^+ \nu_{l}$ to be $\alpha_{\Lambda_c} =-0.89\pm{^{0.17}_{0.11}}\pm{^{0.09}_{0.06}}.
Precision Measurement of the $D_s^{*+}- D_s^+$ Mass Difference	We have measured the vector-pseudoscalar mass splitting $M(D_s^{+})-M(D_s^+) = 144.22\pm 0.47\pm 0.37 MeV$, significantly more precise than the previous world average. We minimize the systematic errors by also measuring the vector-pseudoscalar mass difference $M(D^{0})-M(D^0)$ using the radiative decay $D^{0}\rightarrow D^0\gamma$, obtaining $[M(D_s^{+})-M(D_s^+)]-[M(D^{0})-M(D^0)] = 2.09\pm 0.47\pm 0.37 MeV$. This is then combined with our previous high-precision measurement of $M(D^{0})-M(D^0)$, which used the decay $D^{*0}\rightarrow D^0\pi^0$. We also measure the mass difference $M(D_s^+)-M(D^+)=99.5\pm 0.6\pm 0.3$ MeV, using the $\phi\pi^+$ decay modes of the $D_s^+$ and $D^+$ mesons.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Precision Measurement of the $D_s^{+}- D_s^+$ Mass Difference ### Response: We have measured the vector-pseudoscalar mass splitting $M(D_s^{+})-M(D_s^+) = 144.22\pm 0.47\pm 0.37 MeV$, significantly more precise than the previous world average. We minimize the systematic errors by also measuring the vector-pseudoscalar mass difference $M(D^{0})-M(D^0)$ using the radiative decay $D^{0}\rightarrow D^0\gamma$, obtaining $[M(D_s^{+})-M(D_s^+)]-[M(D^{0})-M(D^0)] = 2.09\pm 0.47\pm 0.37 MeV$. This is then combined with our previous high-precision measurement of $M(D^{0})-M(D^0)$, which used the decay $D^{0}\rightarrow D^0\pi^0$. We also measure the mass difference $M(D_s^+)-M(D^+)=99.5\pm 0.6\pm 0.3$ MeV, using the $\phi\pi^+$ decay modes of the $D_s^+$ and $D^+$ mesons.
A Measurement of ${\cal B}(D_s \to ϕl^+ ν)/{cal B}(D_s\to ϕπ^+)$	Using the CLEO~II detector at CESR, we have measured the ratio of branching fractions ${\cal B}(D_s^+ \to \phi e^+ \nu)/{\cal B}(D_s^+ \to \phi\pi^+) = 0.54\pm 0.05\pm 0.04$. We use this measurement to obtain a model dependent estimate of ${\cal B}(D_s^+ \to \phi \pi^+)$.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: A Measurement of ${\cal B}(D_s \to ϕl^+ ν)/{cal B}(D_s\to ϕπ^+)$ ### Response: Using the CLEO~II detector at CESR, we have measured the ratio of branching fractions ${\cal B}(D_s^+ \to \phi e^+ \nu)/{\cal B}(D_s^+ \to \phi\pi^+) = 0.54\pm 0.05\pm 0.04$. We use this measurement to obtain a model dependent estimate of ${\cal B}(D_s^+ \to \phi \pi^+)$.
Measurement of Cabibbo Suppressed Decays of the $τ$ Lepton	Branching ratios for the dominant Cabibbo-suppressed decays of the $\tau$ lepton have been measured by CLEO~II in $e^+ e^-$ annihilation at CESR ($\sqrt{s} \sim 10.6$~GeV) using kaons with momenta below $0.7\ \rm GeV/c$. The inclusive branching ratio into one charged kaon is $(1.60 \pm 0.12 \pm 0.19)\%$. For the exclusive decays, $B(\tau \to K^-) = (0.66 \pm 0.07 \pm 0.09)\%$, $B(\tau \to K^- \pi^0) = (0.51 \pm 0.10 \pm 0.07)\%$, and, based on three events, $B(\tau \to K^- \pi^0 \pi^0) < 0.3\%$ at the 90\% confidence level. These represent significant improvements over previous results. $B(\tau\to K^- \pi^0)$ is measured for the first time with exclusive $\pi^0$ reconstruction.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Measurement of Cabibbo Suppressed Decays of the $τ$ Lepton ### Response: Branching ratios for the dominant Cabibbo-suppressed decays of the $\tau$ lepton have been measured by CLEO~II in $e^+ e^-$ annihilation at CESR ($\sqrt{s} \sim 10.6$~GeV) using kaons with momenta below $0.7\ \rm GeV/c$. The inclusive branching ratio into one charged kaon is $(1.60 \pm 0.12 \pm 0.19)\%$. For the exclusive decays, $B(\tau \to K^-) = (0.66 \pm 0.07 \pm 0.09)\%$, $B(\tau \to K^- \pi^0) = (0.51 \pm 0.10 \pm 0.07)\%$, and, based on three events, $B(\tau \to K^- \pi^0 \pi^0) < 0.3\%$ at the 90\% confidence level. These represent significant improvements over previous results. $B(\tau\to K^- \pi^0)$ is measured for the first time with exclusive $\pi^0$ reconstruction.
Production and Decay of D_1(2420)^0 and D_2^*(2460)^0	We have investigated $D^{+}\pi^{-}$ and $D^{+}\pi^{-}$ final states and observed the two established $L=1$ charmed mesons, the $D_1(2420)^0$ with mass $2421^{+1+2}_{-2-2}$ MeV/c$^{2}$ and width $20^{+6+3}_{-5-3}$ MeV/c$^{2}$ and the $D_2^(2460)^0$ with mass $2465 \pm 3 \pm 3$ MeV/c$^{2}$ and width $28^{+8+6}_{-7-6}$ MeV/c$^{2}$. Properties of these final states, including their decay angular distributions and spin-parity assignments, have been studied. We identify these two mesons as the $j_{light}=3/2$ doublet predicted by HQET. We also obtain constraints on {\footnotesize $\Gamma_S/(\Gamma_S + \Gamma_D)$} as a function of the cosine of the relative phase of the two amplitudes in the $D_1(2420)^0$ decay.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Production and Decay of D_1(2420)^0 and D_2^(2460)^0 ### Response: We have investigated $D^{+}\pi^{-}$ and $D^{+}\pi^{-}$ final states and observed the two established $L=1$ charmed mesons, the $D_1(2420)^0$ with mass $2421^{+1+2}_{-2-2}$ MeV/c$^{2}$ and width $20^{+6+3}_{-5-3}$ MeV/c$^{2}$ and the $D_2^*(2460)^0$ with mass $2465 \pm 3 \pm 3$ MeV/c$^{2}$ and width $28^{+8+6}_{-7-6}$ MeV/c$^{2}$. Properties of these final states, including their decay angular distributions and spin-parity assignments, have been studied. We identify these two mesons as the $j_{light}=3/2$ doublet predicted by HQET. We also obtain constraints on {\footnotesize $\Gamma_S/(\Gamma_S + \Gamma_D)$} as a function of the cosine of the relative phase of the two amplitudes in the $D_1(2420)^0$ decay.
Two-Photon Production of Charged Pion and Kaon Pairs	A measurement of the cross section for the combined two-photon production of charged pion and kaon pairs is performed using 1.2~$\rm fb^{-1}$ of data collected by the CLEO~II detector at the Cornell Electron Storage Ring. The cross section is measured at invariant masses of the two-photon system between 1.5 and 5.0 GeV/$c^2$, and at scattering angles more than $53^\circ$ away from the $\gamma\gamma$ collision axis in the $\gamma\gamma$ center-of-mass frame. The large background of leptonic events is suppressed by utilizing the CsI calorimeter in conjunction with the muon chamber system. The reported cross section is compared with leading order QCD models as well as previous experiments. In particular, although the functional dependence of the measured cross section disagrees with leading order QCD at small values of the two-photon invariant mass, the data show a transition to perturbative behavior at an invariant mass of approximately 2.5 GeV/$c^2$. hardcopies with figures can be obtained by writing to to: Pam Morehouse preprint secretary Newman Lab Cornell University Ithaca, NY 14853 or by sending mail to: preprints@lns62.this http URL	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Two-Photon Production of Charged Pion and Kaon Pairs ### Response: A measurement of the cross section for the combined two-photon production of charged pion and kaon pairs is performed using 1.2~$\rm fb^{-1}$ of data collected by the CLEO~II detector at the Cornell Electron Storage Ring. The cross section is measured at invariant masses of the two-photon system between 1.5 and 5.0 GeV/$c^2$, and at scattering angles more than $53^\circ$ away from the $\gamma\gamma$ collision axis in the $\gamma\gamma$ center-of-mass frame. The large background of leptonic events is suppressed by utilizing the CsI calorimeter in conjunction with the muon chamber system. The reported cross section is compared with leading order QCD models as well as previous experiments. In particular, although the functional dependence of the measured cross section disagrees with leading order QCD at small values of the two-photon invariant mass, the data show a transition to perturbative behavior at an invariant mass of approximately 2.5 GeV/$c^2$. hardcopies with figures can be obtained by writing to to: Pam Morehouse preprint secretary Newman Lab Cornell University Ithaca, NY 14853 or by sending mail to: preprints@lns62.this http URL
Measurement of the Branching Fraction for D^+ \to K^- π^+ π^+	Using the CLEO-II detector at CESR we have measured the ratio of branching fractions, ${\cal B}(D^+\rightarrow K^- \pi^+ \pi^+)/{\cal B}(D^0 \rightarrow K^-\pi^+) = 2.35 \pm 0.16 \pm 0.16$. Our recent measurement of ${\cal B}(D^0 \rightarrow K^-\pi^+)$ then gives ${\cal B}(D^+\rightarrow K^- \pi^+ \pi^+) = (9.3 \pm 0.6 \pm 0.8)\%$.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Measurement of the Branching Fraction for D^+ \to K^- π^+ π^+ ### Response: Using the CLEO-II detector at CESR we have measured the ratio of branching fractions, ${\cal B}(D^+\rightarrow K^- \pi^+ \pi^+)/{\cal B}(D^0 \rightarrow K^-\pi^+) = 2.35 \pm 0.16 \pm 0.16$. Our recent measurement of ${\cal B}(D^0 \rightarrow K^-\pi^+)$ then gives ${\cal B}(D^+\rightarrow K^- \pi^+ \pi^+) = (9.3 \pm 0.6 \pm 0.8)\%$.
Precise Measurement of the Left-Right Cross Section Asymmetry in $Z$ Boson Production by $\ee$ Collisions	We present a precise measurement of the left-right cross section asymmetry ($A_{LR}$) for $Z$ boson production by $\ee$ collisions. The measurement was performed at a center-of-mass energy of 91.26 GeV with the SLD detector at the SLAC Linear Collider (SLC). The luminosity-weighted average polarization of the SLC electron beam was (63.0$\pm$1.1)%. Using a sample of 49,392 $\z0$ decays, we measure $A_{LR}$ to be 0.1628$\pm$0.0071(stat.)$\pm$0.0028(syst.) which determines the effective weak mixing angle to be $\swein=0.2292\pm0.0009({\rm stat.})\pm0.0004({\rm syst.})$.}	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Precise Measurement of the Left-Right Cross Section Asymmetry in $Z$ Boson Production by $\ee$ Collisions ### Response: We present a precise measurement of the left-right cross section asymmetry ($A_{LR}$) for $Z$ boson production by $\ee$ collisions. The measurement was performed at a center-of-mass energy of 91.26 GeV with the SLD detector at the SLAC Linear Collider (SLC). The luminosity-weighted average polarization of the SLC electron beam was (63.0$\pm$1.1)%. Using a sample of 49,392 $\z0$ decays, we measure $A_{LR}$ to be 0.1628$\pm$0.0071(stat.)$\pm$0.0028(syst.) which determines the effective weak mixing angle to be $\swein=0.2292\pm0.0009({\rm stat.})\pm0.0004({\rm syst.})$.}
Measurement of the Spin-Dependent Structure Function $g_1(x)$ of the Proton	We have measured the spin-dependent structure function $g_1^p$ of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003<x<0.7$ and $1\,\mbox{GeV}^2<Q^2<60\,\mbox{GeV}^2$. Its first moment, $\int_0^1 g_1^p(x) dx $, is found to be $0.136 \pm 0.011\,(\mbox{stat.})\pm 0.011\,(\mbox{syst.})$ at $Q^2=10\,\mbox{GeV}^2$. This value is smaller than the prediction of the Ellis--Jaffe sum rule by two standard deviations, and is consistent with previous measurements. A combined analysis of all available proton, deuteron and neutron data confirms the Bjorken sum rule to within $10\%$ of the theoretical value.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Measurement of the Spin-Dependent Structure Function $g_1(x)$ of the Proton ### Response: We have measured the spin-dependent structure function $g_1^p$ of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003<x<0.7$ and $1\,\mbox{GeV}^2<Q^2<60\,\mbox{GeV}^2$. Its first moment, $\int_0^1 g_1^p(x) dx $, is found to be $0.136 \pm 0.011\,(\mbox{stat.})\pm 0.011\,(\mbox{syst.})$ at $Q^2=10\,\mbox{GeV}^2$. This value is smaller than the prediction of the Ellis--Jaffe sum rule by two standard deviations, and is consistent with previous measurements. A combined analysis of all available proton, deuteron and neutron data confirms the Bjorken sum rule to within $10\%$ of the theoretical value.
A Measurement of the Branching Fraction ${\cal B} τ^+ \to h^- π^0 ν_τ$	Using data from the CLEO II detector at CESR, we measure ${\cal B}(\tau^\pm\rightarrow h^\pm\pi^0\nu_\tau)$ where $h^\pm$ refers to either $\pi^\pm$ or $K^\pm$. We use three different methods to measure this branching fraction. The combined result is ${\cal B}(\tau^\pm\rightarrow h^\pm\pi^0\nu_\tau) = 0.2587 \pm 0.0012 \pm 0.0042$, in good agreement with Standard Model predictions. This result, in combination with other precision measurements, reduces the significance of the one-prong problem in tau decays. A postscript version is available through World-Wide-Web in this http URL	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: A Measurement of the Branching Fraction ${\cal B} τ^+ \to h^- π^0 ν_τ$ ### Response: Using data from the CLEO II detector at CESR, we measure ${\cal B}(\tau^\pm\rightarrow h^\pm\pi^0\nu_\tau)$ where $h^\pm$ refers to either $\pi^\pm$ or $K^\pm$. We use three different methods to measure this branching fraction. The combined result is ${\cal B}(\tau^\pm\rightarrow h^\pm\pi^0\nu_\tau) = 0.2587 \pm 0.0012 \pm 0.0042$, in good agreement with Standard Model predictions. This result, in combination with other precision measurements, reduces the significance of the one-prong problem in tau decays. A postscript version is available through World-Wide-Web in this http URL
A Review of Hadronic and Rare B Decays	We review recent experimental results on B meson decays. These include measurements of the inclusive production of charmed and non-charmed mesons and baryons, the reconstruction of a large number of exclusive hadronic final states with charmed mesons, the search for exclusive hadronic final states without charmed mesons, and the first observation of the decay B-> K* gamma which is described by an electromagnetic penguin diagram. The theoretical implications of these results will be considered. The figures can be obtained in postscript format EMAIL from kh@ohstpy.this http URL.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: A Review of Hadronic and Rare B Decays ### Response: We review recent experimental results on B meson decays. These include measurements of the inclusive production of charmed and non-charmed mesons and baryons, the reconstruction of a large number of exclusive hadronic final states with charmed mesons, the search for exclusive hadronic final states without charmed mesons, and the first observation of the decay B-> K* gamma which is described by an electromagnetic penguin diagram. The theoretical implications of these results will be considered. The figures can be obtained in postscript format EMAIL from kh@ohstpy.this http URL.
New Upper Limit for the Branching Ratio of the Omega- to Xi- gamma Radiative Decay	We have searched for the rare hyperon radiative decay Omega- to Xi- gamma, using the Fermilab Proton Center 375 GeV/c charged hyperon beam. Our measurement of the Omega- beam fraction at 13.6 m from production is (4.8 +_ 0.4)10(-5). No signal was found and we determine a new upper limit of (4.6 x 10-4) at 90% CL for the Omega- to Xi- gamma branching ratio.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: New Upper Limit for the Branching Ratio of the Omega- to Xi- gamma Radiative Decay ### Response: We have searched for the rare hyperon radiative decay Omega- to Xi- gamma, using the Fermilab Proton Center 375 GeV/c charged hyperon beam. Our measurement of the Omega- beam fraction at 13.6 m from production is (4.8 +_ 0.4)10(-5). No signal was found and we determine a new upper limit of (4.6 x 10-4) at 90% CL for the Omega- to Xi- gamma branching ratio.
Experimental momentum spectra of identified hadrons in jets and the predictions from LPHD + MLLA	Experimental data on the shape of hadronic momentum spectra are compared with theoretical predictions in the context of calculations in the Modified Leading Log Approximation (MLLA), under the assumption of Local Parton Hadron Duality (LPHD). Considered are experimental measurements at $e^+e^-$-colliders of $\xi_p^$, the position of the maximum in the distribution of $\xi_p=\log(1/x_p)$, where $x_p=p/p_{beam}$. The parameter $\xi_p^$ is determined for various hadrons at various centre of mass energies. It is interesting to look at the dependence of $\xi^_p$ on the hadron type. This is used to study the influence of the hadron type on the cut-off scale $Q_0$ in the parton shower development. The dependence of $\xi^_p$ on the centre of mass energy is seen to be described adequately by perturbation theory. The approach is made quantitative by extracting a value of $\alpha_s(m_Z)$ from an overall fit to the scaling behaviour of $\xi^*_p$.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Experimental momentum spectra of identified hadrons in jets and the predictions from LPHD + MLLA ### Response: Experimental data on the shape of hadronic momentum spectra are compared with theoretical predictions in the context of calculations in the Modified Leading Log Approximation (MLLA), under the assumption of Local Parton Hadron Duality (LPHD). Considered are experimental measurements at $e^+e^-$-colliders of $\xi_p^$, the position of the maximum in the distribution of $\xi_p=\log(1/x_p)$, where $x_p=p/p_{beam}$. The parameter $\xi_p^$ is determined for various hadrons at various centre of mass energies. It is interesting to look at the dependence of $\xi^_p$ on the hadron type. This is used to study the influence of the hadron type on the cut-off scale $Q_0$ in the parton shower development. The dependence of $\xi^_p$ on the centre of mass energy is seen to be described adequately by perturbation theory. The approach is made quantitative by extracting a value of $\alpha_s(m_Z)$ from an overall fit to the scaling behaviour of $\xi^*_p$.
An optimal method of moments to measure the charge asymmetry at the $Z^0$	Parity violation at LEP or SLC can be measured through the charge asymmetry. An optimal method of moments is developed here to measure this asymmetry, as well as similar asymmetries. This method is equivalent to the likelihood fit. It is simpler in use, as it gives analytical formulas for both the asymmetry and its statistical error. These formulas give the dependence of the accuracy on the experimental angular acceptance explicitly.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: An optimal method of moments to measure the charge asymmetry at the $Z^0$ ### Response: Parity violation at LEP or SLC can be measured through the charge asymmetry. An optimal method of moments is developed here to measure this asymmetry, as well as similar asymmetries. This method is equivalent to the likelihood fit. It is simpler in use, as it gives analytical formulas for both the asymmetry and its statistical error. These formulas give the dependence of the accuracy on the experimental angular acceptance explicitly.
Observation of Anisotropic Event Shapes and Transverse Flow in Au+Au Collisions at AGS Energy	Event shapes for Au + Au collisions at 11.4 GeV/c per nucleon were studied over nearly the full solid angle with the E877 apparatus. The analysis was performed by Fourier expansion of azimuthal distributions of the transverse energy (E_T) measured in different pseudorapidity intervals. For semicentral collisions a pronounced event anisotropy is identified beyond that expected due to fluctuations in particle multiplicity. The signal decreases for peripheral and very central collisions. The amplitude of the flow signal reaches up to 7% of the mean E_T.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Observation of Anisotropic Event Shapes and Transverse Flow in Au+Au Collisions at AGS Energy ### Response: Event shapes for Au + Au collisions at 11.4 GeV/c per nucleon were studied over nearly the full solid angle with the E877 apparatus. The analysis was performed by Fourier expansion of azimuthal distributions of the transverse energy (E_T) measured in different pseudorapidity intervals. For semicentral collisions a pronounced event anisotropy is identified beyond that expected due to fluctuations in particle multiplicity. The signal decreases for peripheral and very central collisions. The amplitude of the flow signal reaches up to 7% of the mean E_T.
Measurement of the Charged Multiplicity of $Z \rightarrow b \overline{b}$ Events	Using an impact parameter tag to select an enriched sample of $Z \rightarrow b \overline{b}$ events, we have measured the difference between the average charged multiplicity of $Z \rightarrow b \overline{b}$ and $Z^0 \rightarrow hadrons$ to be $\overline{n}_{b} - \overline{n}_{had} = 2.24\pm 0.30(\rm{stat.}) \pm 0.33(\rm{syst.})$ tracks per event. {}From this, we have derived $\overline{n}_{b} - \overline{n}_{uds} = 3.31 \pm 0.41 \pm 0.79.$ Comparing this measurement with those at lower center-of-mass energies, we find no evidence that $\overline{n}_{b} - \overline{n}_{uds}$ depends on energy. This result is in agreement with a precise prediction of perturbative QCD, and supports the notion that QCD remains asymptotically free down to the scale $M_b^2$.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Measurement of the Charged Multiplicity of $Z \rightarrow b \overline{b}$ Events ### Response: Using an impact parameter tag to select an enriched sample of $Z \rightarrow b \overline{b}$ events, we have measured the difference between the average charged multiplicity of $Z \rightarrow b \overline{b}$ and $Z^0 \rightarrow hadrons$ to be $\overline{n}_{b} - \overline{n}_{had} = 2.24\pm 0.30(\rm{stat.}) \pm 0.33(\rm{syst.})$ tracks per event. {}From this, we have derived $\overline{n}_{b} - \overline{n}_{uds} = 3.31 \pm 0.41 \pm 0.79.$ Comparing this measurement with those at lower center-of-mass energies, we find no evidence that $\overline{n}_{b} - \overline{n}_{uds}$ depends on energy. This result is in agreement with a precise prediction of perturbative QCD, and supports the notion that QCD remains asymptotically free down to the scale $M_b^2$.
Evidence for Top Quark Production in $\bar{p}p$ Collisions at $\sqrt{s}=1.8$ TeV	We summarize a search for the top quark with the Collider Detector at Fermilab (CDF) in a sample of $\bar{p}p$ collisions at $\sqrt{s}$= 1.8 TeV with an integrated luminosity of 19.3~pb$^{-1}$. We find 12 events consistent with either two $W$ bosons, or a $W$ boson and at least one $b$ jet. The probability that the measured yield is consistent with the background is 0.26%. Though the statistics are too limited to establish firmly the existence of the top quark, a natural interpretation of the excess is that it is due to $t\bar{t}$ production. Under this assumption, constrained fits to individual events yield a top quark mass of $174 \pm 10^{+13}_{-12}$ GeV/c$^2$. The $t\bar{t}$ production cross section is measured to be $13.9^{+6.1}_{-4.8}$~pb. (Submitted to Physical Review Letters on May 16, 1994).	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Evidence for Top Quark Production in $\bar{p}p$ Collisions at $\sqrt{s}=1.8$ TeV ### Response: We summarize a search for the top quark with the Collider Detector at Fermilab (CDF) in a sample of $\bar{p}p$ collisions at $\sqrt{s}$= 1.8 TeV with an integrated luminosity of 19.3~pb$^{-1}$. We find 12 events consistent with either two $W$ bosons, or a $W$ boson and at least one $b$ jet. The probability that the measured yield is consistent with the background is 0.26%. Though the statistics are too limited to establish firmly the existence of the top quark, a natural interpretation of the excess is that it is due to $t\bar{t}$ production. Under this assumption, constrained fits to individual events yield a top quark mass of $174 \pm 10^{+13}_{-12}$ GeV/c$^2$. The $t\bar{t}$ production cross section is measured to be $13.9^{+6.1}_{-4.8}$~pb. (Submitted to Physical Review Letters on May 16, 1994).
Measurement of alpha-s from energy-energy correlations at the Z0 resonance	We have determined the strong coupling alpha-s from a comprehensive study of energy-energy correlations (EEC) and their asymmetry (AEEC) in hadronic decays of Z0 bosons collected by the SLD experiment at SLAC. The data were compared with all four available predictions of QCD calculated up to O(alpha-s2) in perturbation theory, and also with a resummed calculation matched to all four of these calculations. We find large discrepancies between alpha-s values extracted from the different O(alpha-s2) calculations. We also find a large renormalization scale ambiguity in alpha-s determined from the EEC using the O(alpha-s**2) calculations; this ambiguity is reduced in the case of the AEEC, and is very small when the matched calculations are used. Averaging over all calculations, and over the EEC and AEEC results, we obtain alpha-s(MZ)=0.124+0.003-0.004(exp.) +-0.009(theory).	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Measurement of alpha-s from energy-energy correlations at the Z0 resonance ### Response: We have determined the strong coupling alpha-s from a comprehensive study of energy-energy correlations (EEC) and their asymmetry (AEEC) in hadronic decays of Z0 bosons collected by the SLD experiment at SLAC. The data were compared with all four available predictions of QCD calculated up to O(alpha-s2) in perturbation theory, and also with a resummed calculation matched to all four of these calculations. We find large discrepancies between alpha-s values extracted from the different O(alpha-s2) calculations. We also find a large renormalization scale ambiguity in alpha-s determined from the EEC using the O(alpha-s**2) calculations; this ambiguity is reduced in the case of the AEEC, and is very small when the matched calculations are used. Averaging over all calculations, and over the EEC and AEEC results, we obtain alpha-s(MZ)=0.124+0.003-0.004(exp.) +-0.009(theory).
Cumulant to Factorial Moment Ratio and Multiplicity Data	The ratio of cumulant to factorial moments of experimental multiplicity distributions has been calculated for $e^{+}e^{-}$ and $hh$ interactions in a wide range of energies. As a function of the rank it exhibits an initial steep decrease and a series of oscillations around zero. Those features cannot be reproduced by the Negative Binomial Distribution. A comparable behaviour is instead predicted in high-energy perturbative QCD. The presence of a qualitatively similar behaviour for different processes and in wide energy intervals suggests speaking of an approximate scaling of the cumulant to factorial moment ratio.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Cumulant to Factorial Moment Ratio and Multiplicity Data ### Response: The ratio of cumulant to factorial moments of experimental multiplicity distributions has been calculated for $e^{+}e^{-}$ and $hh$ interactions in a wide range of energies. As a function of the rank it exhibits an initial steep decrease and a series of oscillations around zero. Those features cannot be reproduced by the Negative Binomial Distribution. A comparable behaviour is instead predicted in high-energy perturbative QCD. The presence of a qualitatively similar behaviour for different processes and in wide energy intervals suggests speaking of an approximate scaling of the cumulant to factorial moment ratio.
A Precise Measurement of the Weak Mixing Angle in Neutrino-Nucleon Scattering	We report a precise measurement of the weak mixing angle from the ratio of neutral current to charged current inclusive cross-sections in deep-inelastic neutrino-nucleon scattering. The data were gathered at the CCFR neutrino detector in the Fermilab quadrupole-triplet neutrino beam, with neutrino energies up to 600 GeV. Using the on-shell definition, ${\rm sin ^2\theta_W} \equiv 1 - \frac{{\rm M_W} ^2}{{\rm M_Z} ^2}$, we obtain ${\rm sin ^2\theta_W} = 0.2218 \pm 0.0025 ({\rm stat.}) \pm 0.0036 ({\rm exp.\: syst.}) \pm 0.0040 ({\rm model})$.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: A Precise Measurement of the Weak Mixing Angle in Neutrino-Nucleon Scattering ### Response: We report a precise measurement of the weak mixing angle from the ratio of neutral current to charged current inclusive cross-sections in deep-inelastic neutrino-nucleon scattering. The data were gathered at the CCFR neutrino detector in the Fermilab quadrupole-triplet neutrino beam, with neutrino energies up to 600 GeV. Using the on-shell definition, ${\rm sin ^2\theta_W} \equiv 1 - \frac{{\rm M_W} ^2}{{\rm M_Z} ^2}$, we obtain ${\rm sin ^2\theta_W} = 0.2218 \pm 0.0025 ({\rm stat.}) \pm 0.0036 ({\rm exp.\: syst.}) \pm 0.0040 ({\rm model})$.
Phase transition time delays in irradiated superheated superconducting granules	The time difference between a particle interaction in a Superheated Superconducting Granule (SSG) and the resulting phase transition signal has been explored. Detectors containing Zn and Sn SSG were irradiated with neutrons and protons to study the heating mechanism taking place in nuclear recoil and ionizing events. Scattered neutrons have been detected by a scintillator hodoscope behind the SSG with a recoil energy measurement resolution of 10% and an interaction time resolution of 1ns. The fast transition of the metastable granules allowed to determine the elapsed time between an energy deposition and the phase transition signal. In the case of Sn granules, the results show that the time distributions are narrow and independent of the deposited energy in nuclear recoil and ionizing events. In Zn, however, the time distributions are much broader and depend on the energy deposition in the granule.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Phase transition time delays in irradiated superheated superconducting granules ### Response: The time difference between a particle interaction in a Superheated Superconducting Granule (SSG) and the resulting phase transition signal has been explored. Detectors containing Zn and Sn SSG were irradiated with neutrons and protons to study the heating mechanism taking place in nuclear recoil and ionizing events. Scattered neutrons have been detected by a scintillator hodoscope behind the SSG with a recoil energy measurement resolution of 10% and an interaction time resolution of 1ns. The fast transition of the metastable granules allowed to determine the elapsed time between an energy deposition and the phase transition signal. In the case of Sn granules, the results show that the time distributions are narrow and independent of the deposited energy in nuclear recoil and ionizing events. In Zn, however, the time distributions are much broader and depend on the energy deposition in the granule.
Quasiparticle and phonon propagation in superheated superconducting granules after nuclear recoils	The propagation of the excess of quasiparticles and phonons produced by a nuclear recoil inside Sn and Zn superheated superconducting granules will be discussed. The decay towards equilibrium of the initial disturbance is assumed to be a thermal diffusion process described by a set of coupled heat flow equations for the effective quasiparticle and phonon temperatures. The solution is carried out analytically for a point source located anywhere inside the superconducting granule with the initial energy distributed in both quasiparticle and phonon systems. The calculated time delay between the neutron interaction and the nucleation of the phase transition will be compared to the time delay distributions obtained by irradiating Zn and Sn SSG detectors with a 70Me$\!$V neutron beam.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Quasiparticle and phonon propagation in superheated superconducting granules after nuclear recoils ### Response: The propagation of the excess of quasiparticles and phonons produced by a nuclear recoil inside Sn and Zn superheated superconducting granules will be discussed. The decay towards equilibrium of the initial disturbance is assumed to be a thermal diffusion process described by a set of coupled heat flow equations for the effective quasiparticle and phonon temperatures. The solution is carried out analytically for a point source located anywhere inside the superconducting granule with the initial energy distributed in both quasiparticle and phonon systems. The calculated time delay between the neutron interaction and the nucleation of the phase transition will be compared to the time delay distributions obtained by irradiating Zn and Sn SSG detectors with a 70Me$\!$V neutron beam.
Precise Determination of the Weak Mixing Angle from a measurement of ALR in e+e- -> Z0	In the 1993 SLC/SLD run, the SLD recorded 50,000 $\z0$ events produced by the collision of longitudinally polarized electrons on unpolarized positrons at a center-of-mass energy of 91.26 GeV. The luminosity-weighted average polarization of the SLC electron beam was (63.0$\pm$1.1)\%. We measure the left-right cross-section asymmetry in $\z0$ boson production, $\alr$, to be 0.1628$\pm$0.0071(stat.)$\pm$0.0028(syst.) which determines the effective weak mixing angle to be $\swein=0.2292\pm0.0009({\rm stat.})\pm0.0004({\rm syst.}).$	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Precise Determination of the Weak Mixing Angle from a measurement of ALR in e+e- -> Z0 ### Response: In the 1993 SLC/SLD run, the SLD recorded 50,000 $\z0$ events produced by the collision of longitudinally polarized electrons on unpolarized positrons at a center-of-mass energy of 91.26 GeV. The luminosity-weighted average polarization of the SLC electron beam was (63.0$\pm$1.1)\%. We measure the left-right cross-section asymmetry in $\z0$ boson production, $\alr$, to be 0.1628$\pm$0.0071(stat.)$\pm$0.0028(syst.) which determines the effective weak mixing angle to be $\swein=0.2292\pm0.0009({\rm stat.})\pm0.0004({\rm syst.}).$
Polarization of Valence and Sea Quarks in the Proton	Analysis was performed of semi-inclusive and inclusive spin asymmetries determined from the polarized deep inelastic scattering by the Spin Muon Collaboration. Combined analysis of data for polarized deuterium and hydrogen targets allows for separate determination of spin carried by valence {\it u} and {\it d} quarks and non-strange sea quarks as a function of $x_{Bj}$ in the range $0.006<x_{Bj}<0.6$. It was found that polarization of valence {\it u} quarks is positive and of valence {\it d} quarks is negative, whereas the sea polarization is small and consistent with zero within errors.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Polarization of Valence and Sea Quarks in the Proton ### Response: Analysis was performed of semi-inclusive and inclusive spin asymmetries determined from the polarized deep inelastic scattering by the Spin Muon Collaboration. Combined analysis of data for polarized deuterium and hydrogen targets allows for separate determination of spin carried by valence {\it u} and {\it d} quarks and non-strange sea quarks as a function of $x_{Bj}$ in the range $0.006<x_{Bj}<0.6$. It was found that polarization of valence {\it u} quarks is positive and of valence {\it d} quarks is negative, whereas the sea polarization is small and consistent with zero within errors.
LEP asymmetries and fits of the Standard Model	The lepton and quark asymmetries measured at LEP are presented. The results of the Standard Model fits to the electoweak data presented at this conference are given. The top mass obtained from the fit to the LEP data is $172^{+13+18}_{-14-20}$ GeV; it is $177^{+11+18}_{-11-19}$ when also the collider, $\nu$ and $A_{LR}$ data are included.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: LEP asymmetries and fits of the Standard Model ### Response: The lepton and quark asymmetries measured at LEP are presented. The results of the Standard Model fits to the electoweak data presented at this conference are given. The top mass obtained from the fit to the LEP data is $172^{+13+18}_{-14-20}$ GeV; it is $177^{+11+18}_{-11-19}$ when also the collider, $\nu$ and $A_{LR}$ data are included.
Average Multiplicities in Gluon and Quark Jets in Higher-Order Perturbative QCD	The ratio of average multiplicities in gluon and quark jets is shown to become noticeably smaller in higher-order QCD compared to its lowest order value what improves agreement with experiment. QCD anomalous dimension has been calculated. It has been used to get energy dependence of mean multiplicities.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Average Multiplicities in Gluon and Quark Jets in Higher-Order Perturbative QCD ### Response: The ratio of average multiplicities in gluon and quark jets is shown to become noticeably smaller in higher-order QCD compared to its lowest order value what improves agreement with experiment. QCD anomalous dimension has been calculated. It has been used to get energy dependence of mean multiplicities.
A Neural Network for Locating the Primary Vertex in a Pixel Detector	Using simulated collider data for $p+p\rightarrow 2{\rm Jets}\ $ interactions in a 2-barrel pixel detector, a neural network is trained to construct the coordinate of the primary vertex to a high degree of accuracy. Three other estimates of this coordinate are also considered and compared to that of the neural network. It is shown that the network can match the best of the traditional estimates.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: A Neural Network for Locating the Primary Vertex in a Pixel Detector ### Response: Using simulated collider data for $p+p\rightarrow 2{\rm Jets}\ $ interactions in a 2-barrel pixel detector, a neural network is trained to construct the coordinate of the primary vertex to a high degree of accuracy. Three other estimates of this coordinate are also considered and compared to that of the neural network. It is shown that the network can match the best of the traditional estimates.
Semileptonic Branching Fraction of Charged and Neutral B Mesons	An examination of leptons in ${\Upsilon (4S)}$ events tagged by reconstructed $B$ decays yields semileptonic branching fractions of $b_-=(10.1 \pm 1.8\pm 1.4)\%$ for charged and $b_0=(10.9 \pm 0.7\pm 1.1)\%$ for neutral $B$ mesons. This is the first measurement for charged $B$. Assuming equality of the charged and neutral semileptonic widths, the ratio $b_-/b_0=0.93 \pm 0.18 \pm 0.12$ is equivalent to the ratio of lifetimes. A postscript version is available through World-Wide-Web in this http URL	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Semileptonic Branching Fraction of Charged and Neutral B Mesons ### Response: An examination of leptons in ${\Upsilon (4S)}$ events tagged by reconstructed $B$ decays yields semileptonic branching fractions of $b_-=(10.1 \pm 1.8\pm 1.4)\%$ for charged and $b_0=(10.9 \pm 0.7\pm 1.1)\%$ for neutral $B$ mesons. This is the first measurement for charged $B$. Assuming equality of the charged and neutral semileptonic widths, the ratio $b_-/b_0=0.93 \pm 0.18 \pm 0.12$ is equivalent to the ratio of lifetimes. A postscript version is available through World-Wide-Web in this http URL
Measurement of the B -> D^* l nu Branching Fractions and \|Vcb\|	We study the exclusive semileptonic B meson decays B- -> D0 l- nu and B0 -> D+ l- nu using data collected with the CLEO II detector at CESR. We present measurements of the branching fractions B(B0 -> D+ l-nu) = 0.5/f00 [4.49+/-0.32+/-0.39]% and B(B- -> D0 l-nu) = 0.5/f+-[5.13+/-0.54+/-0.64]%, where f00 and f+- are the neutral and charged B meson production fractions at the Upsilon(4s) resonance. Assuming isospion invariance and taking the charged to neutral B meson lifetimes measured at higher energy machines, we determine the ratio f+-/f00=1.04+/-0.14+/-0.13+-/-0.10; further assuming f+- + f00 = 1 we also determine the partial width G(B->D* l nu) = 29.9+/-1.9+/-2.7+/-2.0 ns-1 (independent of f+-/f00). From this partial width we calculate B -> D* l nu branching fractions that do not depend on f+-/f00, nor the individual B lifetimes, but only on the charged to neutral lifetime ratio. The product of the CKM matrix element \|Vcb\| times the normalization of the decay form factor at the point of zero recoil of the D* meson, F(y=1), is determined from a linear fit to the combined differential decay rate of the exclusive B->D* l nu decays: \|Vcb\|F(y) = 0.0351 +/- 0.0019 +/- 0.0018 +/- 0.0008. Using theoretical calculations of the form factor normalization we extract a value for \|Vcb\|. LATEX (REVTEX style) file with uuencoded figures attached (uses PSBOX). Available on WWW this http URL	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Measurement of the B -> D^* l nu Branching Fractions and \|Vcb\| ### Response: We study the exclusive semileptonic B meson decays B- -> D0 l- nu and B0 -> D+ l- nu using data collected with the CLEO II detector at CESR. We present measurements of the branching fractions B(B0 -> D+ l-nu) = 0.5/f00 [4.49+/-0.32+/-0.39]% and B(B- -> D0 l-nu) = 0.5/f+-[5.13+/-0.54+/-0.64]%, where f00 and f+- are the neutral and charged B meson production fractions at the Upsilon(4s) resonance. Assuming isospion invariance and taking the charged to neutral B meson lifetimes measured at higher energy machines, we determine the ratio f+-/f00=1.04+/-0.14+/-0.13+-/-0.10; further assuming f+- + f00 = 1 we also determine the partial width G(B->D* l nu) = 29.9+/-1.9+/-2.7+/-2.0 ns-1 (independent of f+-/f00). From this partial width we calculate B -> D* l nu branching fractions that do not depend on f+-/f00, nor the individual B lifetimes, but only on the charged to neutral lifetime ratio. The product of the CKM matrix element \|Vcb\| times the normalization of the decay form factor at the point of zero recoil of the D* meson, F(y=1), is determined from a linear fit to the combined differential decay rate of the exclusive B->D* l nu decays: \|Vcb\|F(y) = 0.0351 +/- 0.0019 +/- 0.0018 +/- 0.0008. Using theoretical calculations of the form factor normalization we extract a value for \|Vcb\|. LATEX (REVTEX style) file with uuencoded figures attached (uses PSBOX). Available on WWW this http URL
Multiple Scattering Error Propagation in Particle Track Reconstruction	Particle track reconstruction capabilities of the silicon tracking detector system have been studied. As the multiple Coulomb scattering (MCS) induces unavoidable uncertainties on the coordinate measurement, the corresponding error estimates and the associated correlations have been used to find the best track fit parameters and their errors. Finally it permits to find the proper particle characteristics, as vertex position and resolution, flight direction and the error.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Multiple Scattering Error Propagation in Particle Track Reconstruction ### Response: Particle track reconstruction capabilities of the silicon tracking detector system have been studied. As the multiple Coulomb scattering (MCS) induces unavoidable uncertainties on the coordinate measurement, the corresponding error estimates and the associated correlations have been used to find the best track fit parameters and their errors. Finally it permits to find the proper particle characteristics, as vertex position and resolution, flight direction and the error.
Determination of the Strange Quark Content of the Nucleon from a Next-to-Leading-Order QCD Analysis of Neutrino Charm Production	We present the first next-to-leading-order QCD analysis of neutrino charm production, using a sample of 6090 $\nu_\mu$- and $\bar\nu_\mu$-induced opposite-sign dimuon events observed in the CCFR detector at the Fermilab Tevatron. We find that the nucleon strange quark content is suppressed with respect to the non-strange sea quarks by a factor $\kappa = 0.477 \: ^{+\:0.063}_{-\:0.053}$, where the error includes statistical, systematic and QCD scale uncertainties. In contrast to previous leading order analyses, we find that the strange sea $x$-dependence is similar to that of the non-strange sea, and that the measured charm quark mass, $m_c = 1.70 \pm 0.19 \:{\rm GeV/c}^2$, is larger and consistent with that determined in other processes. Further analysis finds that the difference in $x$-distributions between $xs(x)$ and $x\bar s(x)$ is small. A measurement of the Cabibbo-Kobayashi-Maskawa matrix element $\|V_{cd}\|=0.232 ^{+\:0.018}_{-\:0.020}$ is also presented. uufile containing compressed postscript files of five Figures is appended at the end of the LaTeX source.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Determination of the Strange Quark Content of the Nucleon from a Next-to-Leading-Order QCD Analysis of Neutrino Charm Production ### Response: We present the first next-to-leading-order QCD analysis of neutrino charm production, using a sample of 6090 $\nu_\mu$- and $\bar\nu_\mu$-induced opposite-sign dimuon events observed in the CCFR detector at the Fermilab Tevatron. We find that the nucleon strange quark content is suppressed with respect to the non-strange sea quarks by a factor $\kappa = 0.477 \: ^{+\:0.063}_{-\:0.053}$, where the error includes statistical, systematic and QCD scale uncertainties. In contrast to previous leading order analyses, we find that the strange sea $x$-dependence is similar to that of the non-strange sea, and that the measured charm quark mass, $m_c = 1.70 \pm 0.19 \:{\rm GeV/c}^2$, is larger and consistent with that determined in other processes. Further analysis finds that the difference in $x$-distributions between $xs(x)$ and $x\bar s(x)$ is small. A measurement of the Cabibbo-Kobayashi-Maskawa matrix element $\|V_{cd}\|=0.232 ^{+\:0.018}_{-\:0.020}$ is also presented. uufile containing compressed postscript files of five Figures is appended at the end of the LaTeX source.
Supersymmetry at the DiTevatron	We study the signals for supersymmetry at the Tevatron and DiTevatron ($\sqrt{s}=4\TeV$) in various well-motivated supersymmetric models. We consider the trilepton signature in the decay of pair-produced charginos and neutralinos, the missing energy signature in gluino and squark production, and the $b\bar b$ signal in the decay of the lightest supersymmetric Higgs boson produced in association with a $W$ or $Z$ boson. In each case we perform signal and background studies, using Monte Carlo and/or real data to estimate the sensitivity to these signals at the Tevatron and DiTevatron with the Main Injector, for short- and long-term integrated luminosities of ${\cal L}=10$ and $25\ifb$, and $5\sigma$ statistical significance. We conclude that one could probe chargino masses as high as $m_{\chi^\pm_1}\sim180\,(200)\GeV$, gluino masses as high as $m_{\tilde g}\sim450\,(750)\GeV$, and lightest Higgs boson masses as high as $m_h\sim110\,(120)\GeV$ at the Tevatron (DiTevatron). A high-luminosity option at the Tevatron ($10^{33}\cm^{-2}\s^{-1}$) may compensate somewhat for the higher reach of the DiTevatron, but only in the trilepton and Higgs signals. However, these gains may be severely compromised once the multiple-interaction environment of the high-luminosity Tevatron is accounted for.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Supersymmetry at the DiTevatron ### Response: We study the signals for supersymmetry at the Tevatron and DiTevatron ($\sqrt{s}=4\TeV$) in various well-motivated supersymmetric models. We consider the trilepton signature in the decay of pair-produced charginos and neutralinos, the missing energy signature in gluino and squark production, and the $b\bar b$ signal in the decay of the lightest supersymmetric Higgs boson produced in association with a $W$ or $Z$ boson. In each case we perform signal and background studies, using Monte Carlo and/or real data to estimate the sensitivity to these signals at the Tevatron and DiTevatron with the Main Injector, for short- and long-term integrated luminosities of ${\cal L}=10$ and $25\ifb$, and $5\sigma$ statistical significance. We conclude that one could probe chargino masses as high as $m_{\chi^\pm_1}\sim180\,(200)\GeV$, gluino masses as high as $m_{\tilde g}\sim450\,(750)\GeV$, and lightest Higgs boson masses as high as $m_h\sim110\,(120)\GeV$ at the Tevatron (DiTevatron). A high-luminosity option at the Tevatron ($10^{33}\cm^{-2}\s^{-1}$) may compensate somewhat for the higher reach of the DiTevatron, but only in the trilepton and Higgs signals. However, these gains may be severely compromised once the multiple-interaction environment of the high-luminosity Tevatron is accounted for.
A light stop and its consequences at the Tevatron and LEPII	An interesting prediction of a string-inspired {\em one-parameter} $SU(5)\times U(1)$ supergravity model, is the fact that the lightest member ($\tilde t_1$) of the top-squark doublet $(\tilde t_1,\tilde t_2)$, may be substantially lighter than the top quark. This sparticle ($\tilde t_1$) may be readily pair-produced at the Tevatron and, if $m_{\tilde t_1}\lsim130\GeV$, even be observed at the end of Run IB. Top-squark production may also be an important source of sought-for top-quark signatures in the dilepton and $\ell$+jets channels. Therefore, a re-analysis of the top data sample in the presence of a possibly light top-squark appears necessary before definitive statements concerning the discovery of the top quark can be made. Such a light top-squark is linked with a light supersymmetric spectrum, which can certainly be searched for at the Tevatron through trilepton and squark-gluino searches, and at LEPII through direct $\tilde t_1$ pair-production (for $m_{\tilde t_1}\lsim100\GeV$) and via chargino and Higgs-boson searches.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: A light stop and its consequences at the Tevatron and LEPII ### Response: An interesting prediction of a string-inspired {\em one-parameter} $SU(5)\times U(1)$ supergravity model, is the fact that the lightest member ($\tilde t_1$) of the top-squark doublet $(\tilde t_1,\tilde t_2)$, may be substantially lighter than the top quark. This sparticle ($\tilde t_1$) may be readily pair-produced at the Tevatron and, if $m_{\tilde t_1}\lsim130\GeV$, even be observed at the end of Run IB. Top-squark production may also be an important source of sought-for top-quark signatures in the dilepton and $\ell$+jets channels. Therefore, a re-analysis of the top data sample in the presence of a possibly light top-squark appears necessary before definitive statements concerning the discovery of the top quark can be made. Such a light top-squark is linked with a light supersymmetric spectrum, which can certainly be searched for at the Tevatron through trilepton and squark-gluino searches, and at LEPII through direct $\tilde t_1$ pair-production (for $m_{\tilde t_1}\lsim100\GeV$) and via chargino and Higgs-boson searches.
Deep Inelastic Electropion Production	This paper is devoted to a study of possible scaling laws, and their logarithmic corrections, occurring in deep inelastic electropion production. Both the exclusive and semi-exclusive processes are considered. Scaling laws, originally motivated from PCAC and current algebra considerations are examined, first in the framework of the parton model and QCD peturbation theory and then from the more formal perspective of the operator product expansion and asymptotic freedom, (as expressed through the renormalization group). We emphasize that these processes allow scaling to be probed for the full amplitude rather than just its absorbtive part (as is the case in the conventional structure functions). Because of this it is not possible to give a formal derivation of scaling for deep inelastic electropion production processes even if one believes that they are unambiguously sensitive to the light cone behavior of the operator product. The origin of this is shown to be related to its behavior near $x\approx 0$. Investigations, both theoretical and experimental, of these processes is therefore strongly encouraged.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Deep Inelastic Electropion Production ### Response: This paper is devoted to a study of possible scaling laws, and their logarithmic corrections, occurring in deep inelastic electropion production. Both the exclusive and semi-exclusive processes are considered. Scaling laws, originally motivated from PCAC and current algebra considerations are examined, first in the framework of the parton model and QCD peturbation theory and then from the more formal perspective of the operator product expansion and asymptotic freedom, (as expressed through the renormalization group). We emphasize that these processes allow scaling to be probed for the full amplitude rather than just its absorbtive part (as is the case in the conventional structure functions). Because of this it is not possible to give a formal derivation of scaling for deep inelastic electropion production processes even if one believes that they are unambiguously sensitive to the light cone behavior of the operator product. The origin of this is shown to be related to its behavior near $x\approx 0$. Investigations, both theoretical and experimental, of these processes is therefore strongly encouraged.
Top-Quark Production and Flavor Physics	Because of the top quark's very large mass, about 175~GeV, it now provides the best window into flavor physics. Thus, pair--production of top quarks at the Tevatron Collider is the best probe of this physics until the Large Hadron Collider turns on in the next century. I will discuss aspects of the mass and angular distributions that can be measured in $\ttb$ production with the coming large data samples from the Tevatron and even larger ones from the LHC.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Top-Quark Production and Flavor Physics ### Response: Because of the top quark's very large mass, about 175~GeV, it now provides the best window into flavor physics. Thus, pair--production of top quarks at the Tevatron Collider is the best probe of this physics until the Large Hadron Collider turns on in the next century. I will discuss aspects of the mass and angular distributions that can be measured in $\ttb$ production with the coming large data samples from the Tevatron and even larger ones from the LHC.
Sensitivity Of Dark Matter Dectectors To Susy Dark Matter	The sensitivity of dark matter detectors to the lightest neutralino (${\tilde {Z}_1}$) is considered within the framework of supergravity grand unification with radiative breaking of SU(2)xU(1). The relic density of the ${\tilde {Z}_1}$ is constrained to obey $0.10 \leq \Omega_{\tilde {Z}_1}h^2 \leq 0.35$, consistent with COBE data and current measurements of the Hubble constant. Detectors can be divided into two classes: those most sensitive to spin dependent incoherent scattering of the ${\tilde {Z}_1}$ (e.g. $CaF_2$) and those most sensitive to spin independent coherent scattering (high A nuclei e.g. Pb). The parameter space is studied over the range of $100GeV \leq m_0, m_{\tilde {g}} \leq 1 TeV; 2 \leq tan\beta \leq 20$; and $-2 \leq A_t/m_0 \leq 3$ and it is found that the latter type detector is generally more sensitive than the former type. Thus at a sensitivity level of $R \geq 0.1$ events/kg da, a lead detector could scan roughtly 30% of the ~parameter space studied, and an increase of ~this sensitivity by a factor of 10 ~would lead to coverage of about 70% of the parameter space. Dark matter detectors are in general more sensitive to the high $tan\beta$, low $m_{\tilde {g}}$ and low m_0 parts of the parameter space. The conditions of radiative breaking of SU(2)xU(1) enter importantly in analysing the efficiency of dark matter detectors.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Sensitivity Of Dark Matter Dectectors To Susy Dark Matter ### Response: The sensitivity of dark matter detectors to the lightest neutralino (${\tilde {Z}_1}$) is considered within the framework of supergravity grand unification with radiative breaking of SU(2)xU(1). The relic density of the ${\tilde {Z}_1}$ is constrained to obey $0.10 \leq \Omega_{\tilde {Z}_1}h^2 \leq 0.35$, consistent with COBE data and current measurements of the Hubble constant. Detectors can be divided into two classes: those most sensitive to spin dependent incoherent scattering of the ${\tilde {Z}_1}$ (e.g. $CaF_2$) and those most sensitive to spin independent coherent scattering (high A nuclei e.g. Pb). The parameter space is studied over the range of $100GeV \leq m_0, m_{\tilde {g}} \leq 1 TeV; 2 \leq tan\beta \leq 20$; and $-2 \leq A_t/m_0 \leq 3$ and it is found that the latter type detector is generally more sensitive than the former type. Thus at a sensitivity level of $R \geq 0.1$ events/kg da, a lead detector could scan roughtly 30% of the ~parameter space studied, and an increase of ~this sensitivity by a factor of 10 ~would lead to coverage of about 70% of the parameter space. Dark matter detectors are in general more sensitive to the high $tan\beta$, low $m_{\tilde {g}}$ and low m_0 parts of the parameter space. The conditions of radiative breaking of SU(2)xU(1) enter importantly in analysing the efficiency of dark matter detectors.
A Direct Test of Perturbative QCD at Small x	We show that recent data from HERA on the proton structure function $F_2$ at small $x$ and large $Q^2$ provide a direct confirmation of the double asymptotic scaling prediction of perturbative QCD. A linear rise of $\ln F_2$ with the scaling variable $\sigma$ is observed throughout the kinematic region probed at HERA, and the measured slope is in excellent agreement with the QCD prediction. This provides a direct determination of the leading coefficient of the beta function. At large values of the scaling variable $\rho$ the data display a small but statistically significant scaling violation.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: A Direct Test of Perturbative QCD at Small x ### Response: We show that recent data from HERA on the proton structure function $F_2$ at small $x$ and large $Q^2$ provide a direct confirmation of the double asymptotic scaling prediction of perturbative QCD. A linear rise of $\ln F_2$ with the scaling variable $\sigma$ is observed throughout the kinematic region probed at HERA, and the measured slope is in excellent agreement with the QCD prediction. This provides a direct determination of the leading coefficient of the beta function. At large values of the scaling variable $\rho$ the data display a small but statistically significant scaling violation.
Remarks on Koba-Nielsen-Olesen Scaling	It is shown that there is a second properly normalized KNO scaling function, $nP_n(n/\bar n)=\varphi(z)$, which has certain advantages in the analysis of KNO scaling. First, the $nP_n$ are not influenced by the statistical and systematic uncertainties of $\bar n$ hence $\varphi(z)$ provides more selective power than the original KNO scaling function $\bar nP_n(n/\bar n)=\psi(z)$. Second, the new scaling function generates scale parameter $\sigma=1$ since it depends only on the combination of $z$ and the scale parameter of $\psi(z)$. An analysis of $\varphi(z)$ is given using $e^+e^-$ annihilation data for charged particle multiplicity distributions.	### Prompt: Below is an title of a high energy physics paper. Write an abstract of the corresponding paper.### Instruction: Remarks on Koba-Nielsen-Olesen Scaling ### Response: It is shown that there is a second properly normalized KNO scaling function, $nP_n(n/\bar n)=\varphi(z)$, which has certain advantages in the analysis of KNO scaling. First, the $nP_n$ are not influenced by the statistical and systematic uncertainties of $\bar n$ hence $\varphi(z)$ provides more selective power than the original KNO scaling function $\bar nP_n(n/\bar n)=\psi(z)$. Second, the new scaling function generates scale parameter $\sigma=1$ since it depends only on the combination of $z$ and the scale parameter of $\psi(z)$. An analysis of $\varphi(z)$ is given using $e^+e^-$ annihilation data for charged particle multiplicity distributions.