Fri·Oct 1, 2021Friday·October 1, 2021

1. 01*

   Inclusive quarkonium production in pp collisions at $\sqrt{s}=5.02$ TeV

   ALICE Collaboration

   This article reports on the inclusive production cross section of several quarkonium states, $\mathrm{J}/\psi$, $\psi (2S)$, ${\rm Y}(1S)$, ${\rm Y}(2S)$, and ${\rm Y}(3S)$, measured with the ALICE detector at the LHC, in pp collisions at $\sqrt{s}=5.02$ TeV. The analysis is performed in the dimuon decay channel at forward rapidity ($2.5<y<4$). The integrated cross sections and transverse-momentum ($p_{\mathrm{T}}$) and rapidity ($y$) differential cross sections for $\mathrm{J}/\psi$, $\psi (2S)$, ${\rm Y}(1S)$, and the $\psi (2S)$-to-$\mathrm{J}/\psi$ cross section ratios are presented. The integrated cross sections, assuming unpolarized quarkonia, are: ${\sigma }_{\mathrm{J}/\psi }$($p_{\mathrm{T}}<20$ GeV/c) = 5.88 $\pm$ 0.03 $\pm$ 0.34 $\mu$b, ${\sigma }_{\psi (2S)}$($p_{\mathrm{T}}<12$ GeV/c) = 0.87 $\pm$ 0.06 $\pm$ 0.10 $\mu$b, ${\sigma }_{{\rm Y}(1S)}$($p_{\mathrm{T}}<15$ GeV/c) = 45.5 $\pm$ 3.9 $\pm$ 3.5 nb, ${\sigma }_{{\rm Y}(2S)}$($p_{\mathrm{T}}<15$ GeV/c) = 22.4 $\pm$ 3.2 $\pm$ 2.7 nb, and ${\sigma }_{{\rm Y}(3S)}$($p_{\mathrm{T}}<15$ GeV/c) = 4.9 $\pm$ 2.2 $\pm$ 1.0 nb, where the first (second) uncertainty is the statistical (systematic) one. For the first time, the cross sections of the three ${\rm Y}$ states, as well as the $\psi (2S)$ one as a function of $p_{\mathrm{T}}$ and $y$, are measured at $\sqrt{s}=5.02$ TeV at forward rapidity. These measurements also significantly extend the $\mathrm{J}/\psi$ $p_{\mathrm{T}}$ reach and supersede previously published results. A comparison with ALICE measurements in pp collisions at $\sqrt{s}=2.76$, 7, 8, and 13 TeV is presented and the energy dependence of quarkonium production cross sections is discussed. Finally, the results are compared with the predictions from several production models.

   nucl-exhep-exEPJC(2023)·48 citations
2. 02*

   Stopping of 0.3 - 1.2 MeV/u protons and alpha particles in Si

   M. Abdesselam · S. Ouichaoui🇩🇿 · M. Azzouz · A.C. Chami · M. Siad

   The stopping cross sections S (E) of silicon for protons and alpha particles have been measured over the velocity range 0.3-1.2 MeV/u from a SIMOX target using the Rutherford Backscattering Spectrometry (RBS) with special emphasis put on experimental aspects. A detection geometry coupling simultaneously two solid-state Si detectors placed at 165 degrees and 150 degrees relative to each side of the incident beam direction was used to measure the energies of the scattered ions and determine their energy losses within the stopping medium. In this way, the basic energy parameter, Ex, at the Si-SiO2 interface for a given incident energy E0 is the same for ions backscattered in the two directions off both the Si and O target elements, and systematic uncertainties in the S (E) data mainly originating from the target thickness are significantly minimized. A powerful computer code has been elaborated for extracting the relevant S (E) experimental data and the associated overall uncertainty that amounts to less than 3%. The measured S (E) data sets were found to be in fair agreement with H. Paul compilation and with values calculated by the SRIM 06 computer code. In the case of 4He+ ions, experimental data for the gamma-effective charge parameter have been deduced via scaling the measured stopping cross sections to those for protons crossing the same target at the same velocity and compared to the predictions of the SRIM 06 code. It is found that the gamma-parameter values generated by the latter code slightly deviate from experiment over the velocity region around the stopping cross section maximum where strong charge exchanges usually occur.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.B(2008)·2 citations
3. 03*

   Development and characterization of a large area silicon pad array for an electromagnetic calorimeter

   Sourav Mukhopadhyay🇮🇳 · Vinay B. Chandratre🇮🇳 · Sanjib Muhuri🇮🇳 · Rama N. Singaraju🇮🇳 · Jogender Saini🇮🇳 · Tapan K Nayak🇨🇭

   We present the research and development work of the first version of a 6*6 array of silicon pad detectors, carried out in India, for the proposed forward calorimeter (FOCAL) as part of the ALICE collaboration upgrade program at CERN. The primary motivation is to develop a large area silicon pad array realizing the challenging requirements of high-energy physics experiments such as low leakage current, high breakdown voltage and evaluate its performance as an active layer in the prototype silicon tungsten (Si-W) electromagnetic (EM) calorimeter. Towards these goals, a 36-pad silicon sensor with an individual pad size of 1 cm2 is designed on a 4-inch high resistivity N-type wafer and fabricated at Bharat Electronics Limited, Bangalore. The sensors have been used to assemble the prototype Si-W calorimeters and were successfully tested with high-energy particle beams. The design and development of the large area silicon sensor and its characterization using radioactive sources in the laboratory and high-energy particle beams are reported in this paper.

   ↳ physics.ins-dethep-exnucl-exJINST(2021)·5 citations
4. 04*

   Spin Polarization Formula for Dirac Fermions at Local Equilibrium

   Yu-Chen Liu🇨🇳 · Xu-Guang Huang🇨🇳

   We derive a Cooper-Frye type spin polarization formula for Dirac fermions at local thermal equilibrium described by a grand canonical ensemble specified by temperature, fluid velocity, chemical potential, and spin potential. We discuss the physical meaning of different contributions to spin polarization and compare them with previous works. The present formula provides machinery to convert the spin potential computed in, e.g., relativistic spin hydrodynamics to the spin polarization observable in, e.g., heavy-ion collisions.

   ↳ nucl-thhep-phnucl-exSCPMA(2022)·46 citations
5. 05*

   Probing hadronization with flavor correlations of leading particles in jets

   Yang-Ting Chien🇺🇸 · Abhay Deshpande🇺🇸 · Mriganka Mouli Mondal🇺🇸 · George Sterman🇺🇸

   We study nonperturbative flavor correlations between pairs of leading and next-to-leading charged hadrons within jets at the Electron-Ion Collider (EIC). We introduce a charge correlation ratio observable $r_c$ that distinguishes same- and opposite-sign charged pairs. Using Monte Carlo simulations with different event generators, $r_c$ is examined as a function of various kinematic variables for different combinations of hadron species, and the feasibility of such measurements at the EIC is demonstrated. The precision hadronization study we propose will provide new tests of hadronization models and hopefully lead to improved quantitative, and perhaps eventually analytic, understanding of nonperturbative QCD dynamics.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2022)·25 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.