Fri·Jul 21, 2023Friday·July 21, 2023

1. 01*

   Probing high-momentum component in nucleon momentum distribution by neutron-proton bremsstrahlung {\gamma}-rays in heavy ion reactions

   Yuhao Qin · Qinglin Niu · Dong Guo · Sheng Xiao · Baiting Tian · Yijie Wang · Zhi Qin · Xinyue Diao · Fenhai Guan · Dawei Si · Boyuan Zhang · Yaopeng Zhang and 16 other authors

   The high momentum tail (HMT) of nucleons, as a signature of the short-range correlations in nuclei, has been investigated by the high-energy bremsstrahlung $\gamma$ rays produced in ${}^{86}$Kr + ${}^{124}$Sn at 25 MeV/u. The energetic photons are measured by a CsI(Tl) hodoscope mounted on the spectrometer CSHINE. The energy spectrum above 30 MeV can be reproduced by the IBUU model calculations incorporating the photon production channel from $np$ process in which the HMTs of nucleons is considered. A non-zero HMT ratio of about $15\%$ is favored by the data. The effect of the capture channel $np\to d\gamma$ is demonstrated.

   nucl-exPLB(2024)·15 citations
2. 02*

   Measurement of inclusive charged-particle jet production in pp and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   Measurements of inclusive charged-particle jet production in pp and p-Pb collisions at center-of-mass energy per nucleon-nucleon collision $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV and the corresponding nuclear modification factor $R_{\mathrm{pPb}}^{\mathrm{ch}\mathrm{jet}}$ are presented, using data collected with the ALICE detector at the LHC. Jets are reconstructed in the central rapidity region $|{\eta }_{\mathrm{jet}}|<0.5$ from charged particles using the anti-$k_{\mathrm{T}}$ algorithm with resolution parameters $R=0.2$, 0.3, and 0.4. The $p_{\mathrm{T}}$-differential inclusive production cross section of charged-particle jets, as well as the corresponding cross section ratios, are reported for pp and p-Pb collisions in the transverse momentum range $10<p_{\mathrm{T},\mathrm{jet}}^{\mathrm{ch}}<140$ GeV/$c$ and $10<p_{\mathrm{T},\mathrm{jet}}^{\mathrm{ch}}<160$ GeV/$c$, respectively, together with the nuclear modification factor $R_{\mathrm{pPb}}^{\mathrm{ch}\mathrm{jet}}$ in the range $10<p_{\mathrm{T},\mathrm{jet}}^{\mathrm{ch}}<140$ GeV/$c$. The analysis extends the $p_{\mathrm{T}}$ range of the previously-reported charged-particle jet measurements by the ALICE Collaboration. The nuclear modification factor is found to be consistent with one and independent of the jet resolution parameter with the improved precision of this study, indicating that the possible influence of cold nuclear matter effects on the production cross section of charged-particle jets in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV is smaller than the current precision. The obtained results are in agreement with other minimum bias jet measurements available for RHIC and LHC energies, and are well reproduced by the NLO perturbative QCD POWHEG calculations with parton shower provided by PYTHIA8 as well as by JETSCAPE simulations.

   nucl-exhep-exJHEP(2024)·22 citations
3. 03*

   Pseudorapidity dependence of anisotropic flow and its decorrelations using long-range multiparticle correlations in Pb-Pb and Xe-Xe collisions

   ALICE Collaboration

   The pseudorapidity dependence of elliptic ($v_2$), triangular ($v_3$), and quadrangular ($v_4$) flow coefficients of charged particles measured in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV and in Xe-Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV with ALICE at the LHC are presented. The measurements are performed in the pseudorapidity range $-3.5<\eta <5$ for various centrality intervals using two- and multi-particle cumulants with the subevent method. The flow probability density function (p.d.f.) is studied with the ratio of flow coefficient $v_2$ calculated with four- and two-particle cumulant, and suggests that the variance of flow p.d.f. is independent of pseudorapidity. The decorrelation of the flow vector in the longitudinal direction is probed using two-particle correlations. The results measured with respect to different reference regions in pseudorapidity exhibit differences, argued to be a result of saturating decorrelation effect above a certain pseudorapidity separation, in contrast to previous publications which assign this observation to non-flow effects. The results are compared to $3+1$ dimensional hydrodynamic and the AMPT transport model calculations. Neither of the models is able to simultaneously describe the pseudorapidity dependence of measurements of anisotropic flow and its fluctuations. The results presented in this work highlight shortcomings in our current understanding of initial conditions and subsequent system expansion in the longitudinal direction. Therefore, they provide input for its improvement.

   nucl-exhep-exPLB(2024)·9 citations
4. 04*

   Two-pole nature of the $\Lambda (1405)$ from lattice QCD

   John Bulava🇩🇪 · Bárbara Cid-Mora🇩🇪 · Andrew D. Hanlon🇺🇸 · Ben Hörz🇩🇪 · Daniel Mohler🇩🇪 · Colin Morningstar🇺🇸 · Joseph Moscoso🇺🇸 · Amy Nicholson🇺🇸 · Fernando Romero-López🇺🇸 · Sarah Skinner🇺🇸 · André Walker-Loud🇺🇸

   This letter presents the first lattice QCD computation of the coupled channel $\pi \Sigma -\bar{K}N$ scattering amplitudes at energies near $1405\mathrm{MeV}$. These amplitudes contain the resonance $\Lambda (1405)$ with strangeness $S=-1$ and isospin, spin, and parity quantum numbers $I(J^P)=0(1/2^{-})$. However, whether there is a single resonance or two nearby resonance poles in this region is controversial theoretically and experimentally. Using single-baryon and meson-baryon operators to extract the finite-volume stationary-state energies to obtain the scattering amplitudes at slightly unphysical quark masses corresponding to $m_{\pi }\approx 200$ MeV and $m_K\approx 487$ MeV, this study finds the amplitudes exhibit a virtual bound state below the $\pi \Sigma$ threshold in addition to the established resonance pole just below the $\bar{K}N$ threshold. Several parametrizations of the two-channel $K$-matrix are employed to fit the lattice QCD results, all of which support the two-pole picture suggested by $SU(3)$ chiral symmetry and unitarity.

   ↳ hep-lathep-phnucl-exnucl-thPRL(2024)·77 citations
5. 05*

   Study of (3He, t) charge exchange reactions to isobaric analog states in inverse kinematics

   Zhixuan He🇨🇳 · Wenjuan Bu · Chaoyuan Xiao · Meng Li🇨🇳 · Herun Yang🇨🇳 · Bitao Hu · Yi Zhang🇨🇳

   The transition between isobaric analog states (IAS) in the (3He, t) charge exchange reaction presents a unique opportunity to access the isospin structure of the nuclei. In this study not only the Fermi transition but also the Gamow-Teller (G-T) transition of the IAS reaction were investigated for the 13,14C(3He, t) and 17,18,19,20O(3He, t) reactions, in order to explore the neutron number dependence of the IAS reaction for the light neutron-rich nuclei. It was found that the G-T type IAS reaction also exhibited a significant dependence of the transition strength on the neutron number and the angular momentum configuration of the nuclei. Additionally, the inverse kinematics was also discussed for extracting the yields of the interested reaction channels in the proposed experiments on radioactive beams. The calculated triton yields demonstrated the capability of the proposed experiments to obtain meaningful results.

   ↳ nucl-thnucl-ex1 citation

* 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.