An Expression of Interest to Construct a Major SSC Detector

title: Calibration of the Yangbajing Air-shower Core detector using the test beam of BEPCII
abstract: Core detector(YAC) has been developed for the next phase of Tibet air-shower experiment to measure the chemical composition of cosmic rays in “knee” region. A preparation is made for calibration of the linearity of the dynamic range and position dependence of light yield of YAC using test beam of BEPCII. A scraper will be used to attenuate the electron beam intensity from about 10 10 /pulse to 10 2 –10 6 /pulse. A Faraday cup, a thick ionization chamber and a thin ionization chamber are being manufactured to monitor the beam intensity covering dynamic range from 10 2 /pulse to 10 10 /pulse.

title: Determination of the branching ratio of the decay pi 0-->e+e-
abstract: Employing the decay chain K + →π + p 0 , π 0 →e + e - we have observed the decay π 0 →e + e - . With a signal sample of ≃21 events we measure the branching ratio for π 0 →e + e - to be (6.9±2.3±0.6)×10 -8 , normalized to the decay K + →π + p 0 , π 0 →e + e - γ. This result is consistent with the unitarity lower bound and the published 90% confidence level upper limit of 13×10 -8

title: Search for events with large missing transverse momentum, jets, and at least two tau leptons in 7 TeV proton–proton collision data with the ATLAS detector
abstract: A search for events with large missing transverse momentum, jets, and at least two tau leptons has been performed using 2 fb(-1) of proton-proton collision data at root s = 7 TeV recorded with the ...

title: Full supersymmetry simulation for ATLAS in DC1
abstract: This note reports results from a simulation of 100k events for one example of a minimal SUGRA supersymmetry case at the LHC using full simulation of the ATLAS detector. It was carried out as part ATLAS Data Challenge 1.

title: Performance of missing transverse momentum reconstructionin proton-proton collisions at √s = 7 TeV with ATLAS
abstract: The measurement of missing transverse momentum in the ATLAS detector, described in this paper, makes use of the full event reconstruction and a calibration based on reconstructed physics objects. The performance of the missing transverse momentum reconstruction is evaluated using data collected in pp collisions at a centre-of-mass energy of 7 TeV in 2010. Minimum bias events and events with jets of hadrons are used from data samples corresponding to an integrated luminosity of about 0.3 nb^(−1) and 600 nb^(−1) respectively, together with events containing a Z boson decaying to two leptons (electrons or muons) or a W boson decaying to a lepton (electron or muon) and a neutrino, from a data sample corresponding to an integrated luminosity of about 36 pb^(−1). An estimate of the systematic uncertainty on the missing transverse momentum scale is presented.

title: Measurement of $\chi_{cJ}$ decaying into $p\bar{n}\pi^{-}$ and $p\bar{n}\pi^{-}\pi^{0}$
abstract: Using a data sample of $1.06 \times 10^{8}$ $\psip$ events collected with the BESIII detector in 2009, the branching fractions of $\chi_{cJ}\to p\bar{n}\pi^{-}$ and $ p\bar{n}\pi^{-}\pi^{0}$ ($J$=0,1,2) are measured{Throughout the text, inclusion of charge conjugate modes is implied if not stated otherwise.}. The results for $\chi_{c0}\to p\bar{n}\pi^{-}$ and $\chi_{c2}\to p\bar{n}\pi^{-}$ are consistent with, but much more precise than those of previous measurements. The decays of $\chi_{c1}\to p\bar{n}\pi^{-}$ and $ p\bar{n}\pi^{-}\pi^{0}$ are observed for the first time.

title: Recent Results at BESIII
abstract: The BESIII detector operating at the BEPCII e+e− collider collected 2.25 × 108J/ψ events, 1.06 × 108 ψ(3686) events, 2.9 fb−1 data at $${\sqrt s}$$ = 3.773 GeV and 477 pb−1 data at $${\sqrt s}$$ = 4.01 GeV, respectively, by the end of 2011. We report some recent results on light hadron spectroscopy, charmonium spectroscopy and charm physics, which are obtained by analyses of these data.

title: First observation of the isospin violating decay $J/\psi\rightarrow \Lambda\bar{\Sigma}^{0}+c.c.$
abstract: Using a sample of $(225.2\pm 2.8)\times 10^6$ $J/\psi$ events collected with the BESIII detector, we present results of a study of $J/\psi\rightarrow \gamma\Lambda\bar{\Lambda}$ and report the first observation of the isospin violating decay $J/\psi\rightarrow\Lambda\bar{\Sigma}^{0}+c.c.$, in which $\bar{\Sigma}^{0}$ decays to $\gamma \bar{\Lambda}$. The measured branching fractions are $\mathcal{B}(J/\psi\rightarrow\bar{\Lambda}\Sigma^{0}$) = $(1.46\pm0.11\pm0.12) \times10^{-5}$ and $\mathcal{B}(J/\psi\rightarrow\Lambda\bar{\Sigma^{0}}$) = $(1.37\pm0.12\pm0.11) \times10^{-5}$. We search for $\Lambda(1520) \rightarrow \gamma \Lambda$ decay, and find no evident signal, and an upper limit for the product branching fraction $\mathcal{B}(J/\psi\rightarrow\Lambda\bar{\Lambda}(1520)+c.c.)\times \mathcal{B}(\Lambda(1520)\rightarrow\gamma\Lambda)<4.1 \times10^{-6}$ is set at the 90% confidence level. We also report the observation of $\eta_{c}\rightarrow\Lambda\bar{\Lambda}$ in $J/\psi \rightarrow \gamma \eta_{c}$, $\eta_{c}\rightarrow\Lambda\bar{\Lambda}$ and measure the branching fraction $\mathcal{B}(\eta_{c}\rightarrow\Lambda\bar{\Lambda}) =(1.16\pm0.12 (stat)\pm0.19(syst)\pm0.28(PDG))\times10^{-3}$.

title: Search for Invisible Decays of eta and eta-prime in the Processes J/psi ---> phi eta and phi eta-prime
abstract: Using a data sample of 58x10{sup 6} J/{psi} decays collected with the Beijing Spectrometer II detector at the Beijing Electron Positron Collider, searches for invisible decays of {eta} and {eta}{sup '} in J/{psi} to {phi}{eta} and {phi}{eta}{sup '} are performed. The {phi} signals, which are reconstructed in K{sup +}K{sup -} final states, are used to tag the {eta} and {eta}{sup '} decays. No signals are found for the invisible decays of either {eta} or {eta}{sup '}, and upper limits at the 90% confidence level are determined to be 1.65x10{sup -3} for the ratio (B({eta}{yields}invisible)/B({eta}{yields}{gamma}{gamma})) and 6.69x10{sup -2} for (B({eta}{sup '}{yields}invisible)/B({eta}{sup '}{yields}{gamma}{gamma})). These are the first searches for {eta} and {eta}{sup '} decays into invisible final states.

title: Medium-induced multi-photon radiation
abstract: We study the spectrum of multi-photon radiation off a fast quark in medium in the BDMPS/ASW approach. We reproduce the medium-induced one-photon radiation spectrum in dipole approximation, and go on to calculate the two-photon radiation in the Moliere limit. We find that in this limit the LPM effect holds for medium-induced two-photon ladder emission.