SEARCH · Searcharxiv
Search indexed arXiv papers on artificial intelligence, large language models, computer vision and robotics. Read source abstracts and follow links to arXiv.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The measurements of the total inelastic cross section and the differential inelastic cross section as a function of rapidity gap are presented. The data used for these studies were collected in $pp$ collisions at a center-of-mass energy of 7 TeV with the ATLAS detector at the LHC in 2010.
First experimental data on the inclusive yields of Delta^{0}(1232) and Delta^{+}(1232) isobars in neutrino-induced reactions are obtained. Their total yields in neutrino-nucleon interactions, 0.145+-0.055 and 0.182+-0.054, respectively, exceed the value of 0.091+-0.015 obtained recently for the Delta^{++}(1232) state. The data for the all three states of Delta(1232) cannot be reproduced by the LEPTO6.5 model. The fractions of π^0, π^- and π^+ mesons originating from the decay of lightest baryonic and mesonic resonances are estimated to be, respectively 56.6+-9.6%, 39.5+-6.6% and 27.7+-3.2%.
The charge exchange reaction pp $\rightarrow$ n $Δ^{++}$ at high energies is examined. The cross section of this reaction is estimated for RHIC and LHC energies based on data taken at the lower energies of the Intersecting Storage Ring (ISR) at CERN. The interest of such measurements for identifying the associated electromagnetic bremsstrahlung radiation is discussed.
I review the current status of the charge asymmetry in hadronic top-quark pair production from a theory perspective. The standard-model predictions for the observables at the Tevatron and LHC are being discussed, as well as possible explanations of the Tevatron excess in terms of new physics. I give an outlook for future investigations of the top-quark charge asymmetry, focussing on novel observables at the LHC.
Based on the data samples collected at the energies of $J/ψ$, $ψ(3686)$, $ψ(3770)$ and $ψ(4040)$ resonances with the BESIII detector at the BEPCII storage ring, we present charmonium decays in two aspects. One is the search for baryonic decays of $ψ(3770)$ and $ψ(4040)$, including $Λ\barΛπ^+π^-$, $Λ\barΛπ^0$, $Λ\barΛη$, $Σ^+ \barΣ^-$, $Σ^0 \barΣ^0$, $Ξ^-\barΞ^+$ and $Ξ^0\barΞ^0$. None are observed, and upper limits are set at the 90% confidence level. The other is the light hadron spectroscopy from charmonium radiative decays, including the spin-parity analysis of the $p\bar p$ mass-threshold enhancement in $J/ψ$ radiative decays and the $ηη$ system in $J/ψ\toγηη$ radiative decays.
It is shown that the acoustic scaling patterns of anisotropic flow for different event shapes at a fixed collision centrality (shape-engineered events), provide robust constraints for the event-by-event fluctuations in the initial-state density distribution from ultrarelativistic heavy ion collisions. The empirical scaling parameters also provide a dual-path method for extracting the specific shear viscosity $(η/s)_\mathrm{QGP}$ of the quark-gluon plasma (QGP) produced in these collisions. A calibration of these scaling parameters via detailed viscous hydrodynamical model calculations, gives $(η/s)_\mathrm{QGP}$ estimates for the plasma produced in collisions of Au+Au ($\sqrt{s_{NN}}= 0.2$ TeV) and Pb+Pb ($\sqrt{s_{NN}}= 2.76$ TeV). The estimates are insensitive to the initial-state geometry models considered.
The results of analysis SERP-E-184 experiment data, obtained with 70 GeV proton beam irradiation of active target with carbon, silicon and lead plates are presented. For 3-prongs charged charmed mesons decays, event selection criteria were developed and detection efficiency was calculated with detailed simulation using FRITIOF7.02 and GEANT3.21 programs. Signals of decays were found and charm production inclusive cross sections estimated at near threshold energy. The lifetimes and A-dependence of cross section were measured. Yields of D mesons and their ratios in comparison with data of other experiments and theoretical predictions are presented.
This report summarizes the work of the Energy Frontier Top Quark working group of the 2013 Community Summer Study (Snowmass).
This White Paper briefly reviews the present status of the muon (g-2) Standard-Model prediction. This value results in a 3 - 4 standard-deviation difference with the experimental result from Brookhaven E821. The present experimental uncertainty is $\pm 63 \times 10^{-11}$ (0.54~ppm), and the Standard-Model uncertainty is $\simeq \pm 49 \times 10^{-11}$. Fermilab experiment E989 has the goal to reduce the experimental error to $\pm 16 \times 10^{-11}$. Improvements in the Standard-Model value, which should be achieved between now and when the first results from Fermilab E989 could be available, should lead to a Standard-Model uncertainty of $\sim \,\pm 35 \times 10^{-11}$. These improvements would halve the uncertainty on the difference between experiment and theory, and should clarify whether the current difference points toward New Physics, or to a statistical fluctuation. At present, the (g-2) result is arguably the most compelling indicator of physics beyond the Standard Model and, at the very least, it represents a major constraint for speculative new theories such as supersymmetry, dark gauge bosons or extra dimensions.
This is the report of the Snowmass 2013 Computing Frontier Working Group on Distributed Computing and Facility Infrastructures.
A feasibility to use the hadronic decay mode of $Z$ for the model independant measurement of the total cross section of Higgs-strahlung process $(σ_{Zh})$ at a future $e^+e^-$ collider was studied. For the recoil mass measurement from hadronic decay of $Z$, a simple cut based analysis was applied on samples produced by the ILD full detector simulation at $\sqrt{s}=350$ GeV and 500 GeV using the ILC beam parameters. At $350$ GeV, a bump in the recoil mass distribution was reconstructed, and $Δσ_{Zh}/σ_{Zh}$ = 3.4% was obtained assuming 165 fb$^{-1}$ data with $e^-(e^+)$ beam polarization of -80%(+30%) and +80%(-30%), respectively. At $500$ GeV, clear Higgs boson peak in the recoil mass distribution was not seen, however, from the excess of the events, $Δσ_{Zh}/σ_{Zh}=3.9%$ was obtained assuming 500 fb$^{-1}$ data with $e^-(e^+)$ beam polarization of -80%(+30%).
The differential cross-section of elastic proton-proton collisions is studied at ISR and LHC energies, utilizing a quark-diquark model, that generalizes earlier models of Bialas and Bzdak, and, in addition, a model of Glauber and Velasco. These studies suggest that the increase of the total pp cross-section is mainly due to an increase of the separation of the quark and the diquark with increasing energies. Within the investigated class of models, two simple and model-independent phenomenological relations were found, that connect the total pp scattering cross-section to the effective quark, diquark size and their average separation, on one hand, and to the position of the dip of the differential cross-section, on the other hand. The latter t(dip) sigma(tot) ~ const relation can be used to predict t(dip), the position of the dip of elastic pp scattering for future colliding energies, and for other reactions, where sigma(tot) is either known or can be reliably estimated.
The hadronic decay D0 -> KS0 pi+ pi- provides access to the measurement of the mixing parameters of the neutral D-meson system and allows to test for CP violation. A measurement of the mixing parameters x_D and y_D as well as of the parameters |q/p| and phi=arg(q,p), which govern indirect CP violation, will be performed based on a time-dependent amplitude-model analysis of the full LHCb dataset of 2011 and 2012 corresponding to an integrated luminosity of 3/fb.
Computing has become a major component of all particle physics experiments and in many areas of theoretical particle physics. Progress in HEP experiment and theory will require significantly more computing, software development, storage, and networking, with different projects stretching future capabilities in different ways. However, there are many common needs among different areas in HEP, so more community planning is advised to increase efficiency. Careful and continuing review of the topics we studied, i.e., user needs and capabilities of current and future technology, is needed.
Report of the Snowmass CpF-I4 subgroup on Software Development, Staffing and Training
The breaking of the $CP$ symmetry in $D^0$ meson decays has been awaited for a long time. After a set of measurements provided by the LHCb, CDF, and Belle Collaborations leading in march 2012 to combined results that were consistent with no $CP$ violation at a CL of $0.006\%$ suggesting $CP$ violation at $\sim1\%$ level. Such a potentially large value of $CP$ violation in charm decays has triggered widespread interest from the whole particle physics community to evaluate the implications of such an interesting unexpected results. However, a more recent combination of more up-to-date results in March 2013, has slightly changed the situation, showing that data are consistent with the $CP$ conserving hypothesis at $2.1\%$ CL. I briefly review the method used by the various Collaborations when extracting the quantity $ΔA_{CP}$ and the relative results. Finally I discuss the need for additional measurements, and present the potential of a time-dependent analysis when looking for $CP$ violation in $D^0$ decays and how this can be used to largely improve the current sensitivity on the mixing phase $ϕ_{MIX}$.
DANSS is a highly segmented 1m^3 plastic scintillator detector. It's 2500 scintillator strips have a Gd loaded reflective cover. Light is collected with 3 wave length shifting fibers per strip and read out with 50 PMTs and 2500 SiPMs. The DANSS will be installed under the industrial 3 GW reactor of the Kalinin Nuclear Power Plant at distances varying from 9.7m to 12.2m from the reactor core. Tests of the detector prototype DANSSino demonstrated that in spite of a small size (20x20x100 cm^3) it is quite sensitive to reactor antineutrinos, detecting about 70 Inverse Beta Decay events per day with the signal-to-background ratio of about unity. The prototype tests have demonstrated feasibility to reach the design performance of the DANSS detector. The DANSS experiment will detect about 10 thousand antineutrino events per day with a background below ~1%. Detector will be calibrated every day and its position will be changed frequently to reduce systematic errors. These features will provide a high sensitivity to reactor antineutrino oscillations to sterile neutrinos, suggested recently to explain a so-called "reactor anomaly". Data taking will start already next year.
This White Paper provides a supplement to the Snowmass Summary from CF1 (Cosmic Frontier WIMP Direct Detection). It was largely prepared during the August 2013 Community Planning Meeting and relies on information gathered from the larger dark matter community. It is a more detailed answer to the CF1 Charge: "Identify the common infrastructure required to meet the scientific and technical goals of dark matter direct detection." The community as a whole recognizes that sensitive searches for WIMPs require identification, quantification, and procurement of radiopure materials. The lack of sufficient resources in this area is a major project risk for future experiments and can limit scientific reach