ShantanuT01/DACTYL-Pretraining huggingface dataset:
We study predictions for B-physics in a class of models, recently introduced, with a non-supersymmetric warped extra dimension. In these models few ($\sim 3$) TeV Kaluza-Klein masses are consistent with electroweak data due to bulk custodial symmetry. Furthermore, there is an analog of GIM mechanism which is violated by the heavy top quark (just as in SM) leading to striking signals at $B$-factories:(i) New Physics (NP) contributions to $\Delta F= 2$ transitions are comparable to SM. This implies that, within this NP framework, the success of SM unitarity triangle fit is a ``coincidence'' Thus, clean extractions of unitarity angles via e.g. $B \to \pi \pi,\rho \pi, \rho \rho, DK$ are likely to be affected, in addition to O(1) deviation from SM prediction in $B_s$ mixing. (ii) O(1) deviation from SM predictions for $B \to X_s l^+ l^-$ in rate as well as in forward-backward and direct CP asymmetry. (iii) Large mixing-induced CP asymmetry in radiative B decays, wherein the SM unamibgously predicts very small asymmetries. Also with KK masses 3 TeV or less, and with anarchic Yukawa masses, contributions to electric dipole moments of the neutron are roughly 20 times larger than the current experimental bound so that this framework has a "CP problem".
Noncommutative invariant theory is a generalization of the classical invariant theory of the action of $SL(2,\IC)$ on binary forms. The dimensions of the spaces of invariant noncommutative polynomials coincide with the numbers of certain noncrossing partitions. We give an elementary combinatorial explanation of this fact by constructing a noncrossing basis of the homogeneous components. Using the theory free stochastic measures this provides a combinatorial proof of the Molien-Weyl formula in this setting.
We present 2-degree field spectroscopic observations of a sample of 96 A-type stars selected from the Sloan Digital Sky Survey Data Release 3 (SDSS DR3). Our aim is to identify blue horizontal branch (BHB) stars in order to measure the kinematic properties of the tidal tails of the Sagittarius dwarf spheroidal galaxy. We confine our attention to the 44 classifiable stars with spectra of signal-to-noise ratio >15 per angstrom. Classification produces a sample of 29 BHB stars at distances 5-47 kpc from the Sun. We split our sample into three bins based on their distance. We find 10 of the 12 stars at 14-25 kpc appear to have coherent, smoothly varying radial velocities which are plausibly associated with old debris in the Sagittarius tidal stream. Further observations along the orbit and at greater distances are required to trace the full extent of this structure on the sky. Three of our BHB stars in the direction of the globular cluster Palomar (Pal) 5 appear to be in an overdensity but are in the foreground of Pal 5. More observations are required around this overdensity to establish any relation to Pal 5 and/or the Sgr stream. We emphasize observations of BHB stars have unlimited potential for providing accurate velocity and distance information in old distant halo streams and globular clusters alike. The next generation multi-object spectrographs provide an excellent opportunity to accurately trace the full extent of such structures.
Star-forming regions are usually studied in the context of Galactic surveys, but dedicated observations are sometimes needed when the study reaches beyond the survey area. Here, we studied the G345.5+1.5 region, which is located slightly above the Galactic plane, to understand its star formation properties. We combined the LABOCA and $^{12}$CO(4$-$3) transition line observations complemented with the Hi-GAL and $\it{Spitzer}$-GLIMPSE surveys to study the star formation toward this region. We used the Clumpfind algorithm to extract the clumps from the 870$\mu$m and $^{12}$CO(4$-$3) data. Radio emission at 36cm was used to estimate the number of HII regions and to remove the contamination from the free-free emission at 870$\mu$m. We employed color-color diagrams and spectral energy distribution slopes to distinguish between prestellar and protostellar clumps. We studied the boundedness of the clumps through the virial parameter. Finally, we estimated the star formation efficiency and star formation rate of the region and used the Schmidt-Kennicutt diagram to compare its ability to form stars. Of the 13 radio sources that we found using the MGPS-2 catalog, 7 are found to be associated with HII regions corresponding to late-B or early-O stars. We found 45 870$\mu$m clumps, and 107 $^{12}$CO clumps. More than 50\% of the clumps are protostellar and bounded and are able to host star formation. High SFR and SFR density values are associated with the region, with an SFE of a few percent. With submillimeter, CO transition, and short-wavelength infrared observations, our study reveals a population of massive stars, protostellar and bound starless clumps, toward G345.5+1.5. This region is therefore actively forming stars, and its location in the starburst quadrant of the Schmidt-Kennicutt diagram is comparable to other star-forming regions found within the Galactic plane.
A black hole that is ringing down to quiescence emits gravitational radiation of a very specific nature that can inform us of its mass and angular momentum, test the no-hair theorem for black holes, and perhaps even give us additional information about its progenitor system. This paper provides a detailed description of, and investigation into the behavior of, multimode fitting of the ring-down signal provided by numerical simulations. We find that there are at least three well-motivated multimode fitting schemes that can be used. These methods are tested against a specific numerical simulation to allow for comparison to prior work.
Nucleation is considered near the pseudospinodal in a one-dimensional $\phi^4$ model with a non-conserved order parameter and long-range interactions. For a sufficiently large system or a system with slow relaxation to metastable equilibrium, there is a non-negligible probability of nucleation occurring before reaching metastable equilibrium. This process is referred to as transient nucleation. The critical droplet is defined to be the configuration of maximum likelihood that is dynamically balanced between the metastable and stable wells. Time-dependent droplet profiles and nucleation rates are derived, and theoretical results are compared to computer simulation. The analysis reveals a distribution of nucleation times with a distinct peak characteristic of a nonstationary nucleation rate. Under the quench conditions employed, transient critical droplets are more compact than the droplets found in metastable equilibrium simulations and theoretical predictions.
We have performed new fits of our chirally motivated coupled--channels model for meson-baryon interactions and discussed the impact of the SIDDHARTA measurement on the $\bar{K}N$ amplitudes in the free space and in nuclear medium. The kaon--nucleon amplitudes generated by the model are fully consistent with our earlier studies that used the older kaonic hydrogen data by the DEAR collaboration. The subthreshold energy dependence of the in-medium $\bar{K}N$ amplitudes plays a crucial role in $\bar{K}$--nuclear applications.
In this paper we generalize the flux ratio method Bailey et al. (2009) to the case of two luminosity indicators and search the optimal luminosity-flux ratio relations on a set of spectra whose phases are around not only the date of bright light but also other time. With these relations, a new method is proposed to constrain the host galaxy extinction of SN Ia and its distance. It is first applied to the low redshift supernovas and then to the high redshift ones. The results of the low redshift supernovas indicate that the flux ratio method can indeed give well constraint on the host galaxy extinction parameter E(B-V), but weaker constraints on R_{V}. The high redshift supernova spectra are processed by the same method as the low redshift ones besides some differences due to their high redshift. Among 16 high redshift supernovas, 15 are fitted very well except 03D1gt. Based on these distances, Hubble diagram is drew and the contents of the Universe are analyzed. It supports an acceleration behavior in the late Universe. Therefore, the flux ratio method can give constraints on the host galaxy extinction and supernova distance independently. We believe, through further studies, it may provide a precise tool to probe the acceleration of the Universe than before.
We study the limiting distribution of the eigenvalues of the Ginibre ensemble conditioned on the event that a certain proportion lie in a given region of the complex plane. Using an equivalent formulation as an obstacle problem, we describe the optimal distribution and some of its monotonicity properties.
Considering some deposition models with limited mobility, we show that the typical decay of the interface width to its saturation value is exponential, which defines the crossover or saturation time \tau. We present a method to calculate a characteristic time \tau_0 proportional to \tau and estimate the dynamical exponent z. In one dimensional substrates of lengths L <~ 2048, the method is applied to the Family model, the restricted solid-on-solid (RSOS) model and the ballistic deposition. Effective exponents z_L converge to asymptotic values consistent with the corresponding continuum theories. For the two-dimensional Family model, the expected dynamic scaling hypothesis suggests a particular definition of \tau_0 that leads to z=2, improving previous calculations based on data collapse methods. For the two-dimensional RSOS model, we obtain z ~ 1.6 and \alpha < 0.4, in agreement with recent large scale simulations.
We begin to analyze and contrast the predictions for the decay $b\to s\ell^+\ell^-$ in the Left-Right Symmetric Model(LRM) with those of the Standard Model(SM). In particular, we show that the forward-backward asymmetry of the lepton spectrum can be used to distinguish the SM from the simplest manifestation of the LRM. [To appear in the Proceedings of the 2nd International Conference on B Physics and CP Violation, Honolulu, HI, 24-27 March 1997]
We say $G\to (\mathcal{C}, P_n)$ if $G-E(F)$ contains an $n$-vertex path $P_n$ for any spanning forest $F\subset G$. The size Ramsey number $\hat{R}(\mathcal{C}, P_n)$ is the smallest integer $m$ such that there exists a graph $G$ with $m$ edges for which $G\to (\mathcal{C}, P_n)$. Dudek, Khoeini and Pra{\l}at proved that for sufficiently large $n$, $2.0036n \le \hat{R}(\mathcal{C}, P_n)\le 31n$. In this note, we improve both the lower and upper bounds to $2.066n\le \hat{R}(\mathcal{C}, P_n)\le 5.25n+O(1).$ Our construction for the upper bound is completely different than the one considered by Dudek, Khoeini and Pra{\l}at. We also have a computer assisted proof of the upper bound $\hat{R}(\mathcal{C}, P_n)\le \frac{75}{19}n +O(1) < 3.947n $.
We study long time behavior of a discrete time weakly interacting particle system, and the corresponding nonlinear Markov process in $\mathbb{R}^d$, described in terms of a general stochastic evolution equation. In a setting where the state space of the particles is compact such questions have been studied in previous works, however for the case of an unbounded state space very few results are available. Under suitable assumptions on the problem data we study several time asymptotic properties of the $N$-particle system and the associated nonlinear Markov chain. In particular we show that the evolution equation for the law of the nonlinear Markov chain has a unique fixed point and starting from an arbitrary initial condition convergence to the fixed point occurs at an exponential rate. The empirical measure $\mu_{n}^{N}$ of the $N$-particles at time $n$ is shown to converge to the law $\mu_{n}$ of the nonlinear Markov process at time $n$, in the Wasserstein-1 distance, in $L^{1}$, as $N\to \infty$, uniformly in $n$. Several consequences of this uniform convergence are studied, including the interchangeability of the limits $n\to \infty$ and $N\to\infty$ and the propagation of chaos property at $n = \infty$. Rate of convergence of $\mu_{n}^{N}$ to $\mu_{n}$ is studied by establishing uniform in time polynomial and exponential probability concentration estimates.
The uncertainty region of the highly energetic neutrino IceCube200107A includes 3HSP J095507.9+355101 ($z$~=~0.557), an extreme blazar, which was detected in a high, very hard, and variable X-ray state shortly after the neutrino arrival. Following a detailed multi-wavelength investigation, we confirm that the source is a genuine BL Lac, contrary to TXS 0506+056, the first source so far associated with IceCube neutrinos, which is a "masquerading" BL Lac. As in the case of TXS0506+056, 3HSP J095507.9+355101 is also way off the so-called "blazar sequence". We consider 3HSP J095507.9+355101 a possible counterpart to the IceCube neutrino. Finally, we discuss some theoretical implications in terms of neutrino production.
Theoretical models of stellar evolution predict that most of the lithium inside a star is destroyed as the star becomes a red giant. However, observations reveal that about 1% of red giants are peculiarly rich in lithium, often exceeding the amount in the interstellar medium or predicted from the Big Bang. With only about 150 lithium-rich giants discovered in the past four decades, and no distinguishing properties other than lithium enhancement, the origin of lithium-rich giant stars is one of the oldest problems in stellar astrophysics. Here we report the discovery of 2,330 low-mass (1 to 3$\,M_\odot$) lithium-rich giant stars, which we argue are consistent with internal lithium production that is driven by tidal spin-up by a binary companion. Our sample reveals that most lithium-rich giants have helium-burning cores ($80^{+7}_{-6}\%$), and that the frequency of lithium-rich giants rises with increasing stellar metallicity. We find that while planet accretion may explain some lithium-rich giants, it cannot account for the majority that have helium-burning cores. We rule out most other proposed explanations as the primary mechanism for lithium-rich giants, including all stages related to single star evolution. Our analysis shows that giants remain lithium-rich for only about two million years. A prediction from this lithium depletion timescale is that most lithium-rich giants with a helium-burning core have a binary companion.
Eleven different types of "maximally superintegrable" Hamiltonian systems on the real hyperboloid $(s^0)^2-(s^1)^2+(s^2)^2-(s^3)^2=1$ are obtained. All of them correspond to a free Hamiltonian system on the homogeneous space $SU(2,2)/U(2,1)$, but to reductions by different maximal abelian subgroups of $SU(2,2)$. Each of the obtained systems allows 5 functionally independent integrals of motion, from which it is possible to form two or more triplets in involution (each of them includes the hamiltonian). The corresponding classical and quantum equations of motion can be solved by separation of variables on the $O(2,2)$ space.
Magnetism in bare uncapped gold nano-clusters is explored from a density functional theory perspective with scalar relativistic effects included via the pseudo-potential. The computed electronic structures of various nano-clusters reveal that permanent size-dependent spin-polarization appears without geometry relaxation for bare clusters even though bulk gold is diamagnetic. The polarized ground states for clusters are favorable due to the hybridization of the s and d orbitals, and bare octahedral clusters are expected to be magnetic for cluster sizes of approximately 38 atoms and larger. Much larger clusters will be diamagnetic when the surface-to-volume ratio is small and the core diamagnetism prevails. Moderate changes in the inter-atomic distances and cluster geometry are shown not to alter this conclusion. Contrary to LDA and EAM predictions, GGA and hybrid geometry optimizations reveal increased inter-atomic bond distances in bare gold clusters relative to the bulk lattice values. This expansion enhances the preexisting spin polarization.
Motivated by the local flavor of several well-known semi-orthogonal decompositions in algebraic geometry, we introduce a technique called conservative descent, which shows that it is enough to establish these decompositions locally. The decompositions we have in mind are those for projectivized vector bundles and blow-ups, due to Orlov, and root stacks, due to Ishii and Ueda. Our technique simplifies the proofs of these decompositions and establishes them in greater generality for arbitrary algebraic stacks.
In this paper we propose an exact and explicit nonlinear solution to the governing equations which retains all the Coriolis terms. In the presence of an underlying current, we seek the trapped waves induced by these solutions in Northern and Southern hemisphere respectively, showing that the retention of the Coriolis force in the governing equations affects significantly the range of the admissible following and adverse currents.
We extend the two-dimensional two-layer outer gap model to a three-dimensional geometry and use it to study the high-energy emission of the Vela pulsar. In this model, the outer gap is divided into two parts, i.e. the main acceleration region on the top of last-open field lines and the screening region around the upper boundary of the gap. In the main acceleration region, the charge density is much lower than the Goldreich-Julian charge density and the charged particles are accelerated by the electric field along the magnetic field to emit multi-GeV photons. In the screening region, the charge density is larger than the Goldreich-Julian value to close the gap and particles in this region are responsible for multi-100MeV photon emission. We apply this three dimensional two-layer model to the Vela pulsar and compare the model light curves, the phase-averaged spectrum and the phase-resolved spectra with the recent Fermi observations, which also reveals the existence of the third peak between two main peaks. The phase position of the third peak moves with the photon energy, which cannot be explained by the geometry of magnetic field structure and the caustic effects of the photon propagation. We suggest that the existence of the third peak and its energy dependent movement results from the azimuthal structure of the outer gap.
DP-coloring is a generalization of list coloring introduced recently by Dvo\v{r}\'ak and Postle. We prove that for every $n$-vertex graph $G$ whose chromatic number $\chi(G)$ is "close" to $n$, the DP-chromatic number of $G$ equals $\chi(G)$. "Close" here means $\chi(G)\geq n-O(\sqrt{n})$, and we also show that this lower bound is best possible (up to the constant factor in front of $\sqrt{n}$), in contrast to the case of list coloring.
We have investigated the dielectric and magnetic properties of Eu$_{0.595}$Y$_{0.405}$MnO$_{3}$ $without$ the presence of the 4$f$ magnetic moments of the rare earth ions, and have found two ferroelectric phases with polarization along the $a$ and $c$ axes in a zero magnetic field. A magnetic field induced switching from one to the other ferroelectric phase took plase in which the direction of ferroelectric polarization changed from the a axis to the c axis by the application of magnetic fields parallel to the a axis. In contrast to the case of TbMnO$_{3}$, in which the 4$f$ moments of Tb$^{3+}$ ions play an important role in such a ferroelectric phase switching, the magnetic-field-induced switching between ferroelectric phases in Eu$_{0.595}$Y$_{0.405}$MnO$_{3}$ does not originate from the magnetic transition of the rare-earth 4$f$ moments, but from that of the Mn 3$d$ spins.
We consider the dynamical properties of a simple model of vibrational surface modes. We obtain the exact spectrum of surface excitations and discuss their dynamical features. In addition to the usually discussed localized and oscillatory regimes we also find a second phase transition where surface mode frequency becomes purely imaginary and describes an overdamped regime. Noticeably, this transition has an exact correspondence to the oscillatory - overdamped transition of the standard oscillator with a frictional force proportional to velocity.
We have used density functional theory to study the nonlinear screening properties of a two-dimensional (2D) electron gas. In particular, we consider the screening of an external static point charge of magnitude Z as a function of the distance of the charge from the plane of the gas. The self-consistent screening potentials are then used to determine the 2D stopping power in the low velocity limit based on the momentum transfer cross-section. Calculations as a function of Z establish the limits of validity of linear and quadratic response theory calculations, and show that nonlinear screening theory already provides significant corrections in the case of protons. In contrast to the 3D situation, we find that the nonlinearly screened potential supports a bound state even in the high density limit. This behaviour is elucidated with the derivation of a high density screening theorem which proves that the screening charge can be calculated perturbatively in the high density limit for arbitrary dimensions. However, the theorem has particularly interesting implications in 2D where, contrary to expectations, we find that perturbation theory remains valid even when the perturbing potential supports bound states.
Ba_2Cu_3O_4Cl_2 consists of two types of copper atoms, Cu(A) and Cu(B). We study the corresponding Heisenberg model with three antiferromagnetic couplings, J_AA, J_BB and J_AB. We find interesting frustration effects due to the coupling J_AB.
Although AGN feedback through ionised winds is of great importance in models of AGN/galaxy coevolution, the mass and energy output via these winds, even in the nearby universe, is poorly understood. The issue is complicated by the wide range of ionisation in the winds, which means that multiwavelength observational campaigns are required to obtain the complete picture. In this paper, we use a ~ 160 ks XMM-Newton RGS spectrum to get the most accurate view yet of the ionised outflow (warm absorber) in NGC 7469 as seen in X-rays, finding that there is a wide range of ionisation, with log xi in the range ~ 0.5-3.5 erg cm s^-1, and two main velocity regimes, at 580-720 and 2300 km s^-1, with the highest velocity gas being the least ionised. The total absorbing column density in the X-rays is of order 3 x 10^21 cm^-2. We find that the lowest ionisation phase of the absorber is probably identical with one of the phases of the UV absorber discovered in previous studies. We show that both X-ray and UV absorbers are consistent with an origin near the base of a torus wind, where matter is being launched and accelerated. Calculating the mass outflow rate and kinetic luminosity of all the absorber phases, we demonstrate that the X-ray absorbing gas carries respectively ~ 90% and 95% of the mass and kinetic energy output of the ionised outflow.
We study the growth of perturbations in an expanding Bianchi type-I metric that evolves according to an energy density that includes dust and a cosmological constant. Assuming an epoch where the cosmological constant is subdominant, we find that, for a reasonably large set of initial conditions, the metric fluctuations grow fast enough to make the metric inhomogeneous before the cosmological constant becomes the dominant form of energy. We have examined values for the cosmological constant that are in the interval $10^{10} {GeV}$ to $10^{16} {GeV}$.