Tue·Jul 25, 2023Tuesday·July 25, 2023

1. 01*

   Proton induced reactions on 114Sn and 120Sn targets at energies up to 18 MeV

   G.H.Hovhannisyan · T.M.Bakhshiyan · G.V.Martirosyan · R.K.Dallakyan · A.R.Balabekyan

   We measure cross sections of proton-induced reactions on tin up to energies of 18 MeV using the stacked-foil activation technique, and report first experimental values for 114Sn(p,{\alpha})111In, {^{120}}Sn(p,{\alpha})117gIn, and 114Sn(p,x)113Sn reactions. Measured cross sections have been compared to existing experimental values and numerical calculations based on Talys1.95. Our data are in good agreement with all previous experiments, and also with Talys1.95 results except for 120Sn(p,{\alpha})117m,gIn reactions where the numerical calculations are shifted to higher energies. We also measure isomeric cross section ratios for 117m,gIn and 120m,gSb pairs as functions of the incident proton energy.

   nucl-exnucl-thphysics.app-phEPJA(2023)·1 citation
2. 02*

   Elliptic flow of light nuclei in Au+Au collisions at $\sqrt{s_{NN}}$ = 14.6, 19.6, 27, and 54.4 GeV using the STAR detector

   Rishabh Sharma🇮🇳

   Loosely bound light nuclei are produced in abundance in heavy-ion collisions. There are two main possible models to explain their production mechanism - the thermal model and the coalescence model. The thermal model suggests that the light nuclei are produced from a thermal source, where they are in equilibrium with other species present in the fireball. However, due to the small binding energies, the produced nuclei are not likely to survive the high-temperature conditions of the fireball. The coalescence model tries to explain the production of light nuclei by assuming that they are formed at later stages by the coalescence of protons and neutrons near the kinetic freeze-out surface. The final-state coalescence of nucleons will lead to the mass number scaling of the elliptic flow ($v_2$) of light nuclei. This scaling states that the $v_2$ of light nuclei scaled by their respective mass numbers will follow very closely the $v_2$ of nucleons. Therefore, studying the $v_2$ of light nuclei and comparing it with the $v_2$ of protons will help us in understanding their production mechanism. In this talk, we will present the transverse momentum ($p_T$) and centrality dependence of $v_2$ of $d$, $t$, and ${}^3\text{He}$ in Au+Au collisions at $\sqrt{s_{NN}}$ = 14.6, 19.6, 27, and 54.4 GeV. Mass number scaling of $v_2(p_T)$ of light (anti-)nuclei will be shown and physics implications will be discussed.

   nucl-exhep-exhep-ph0 citations
3. 03*

   Identified hadron production at mid-rapidity in Au+Au collisions at $\sqrt{s_{NN}}=54.4$ GeV at STAR

   Krishan Gopal🇮🇳

   Quantum Chromodynamics (QCD) predicts that at sufficiently high temperature ($T$) and/or baryon chemical potential (${\mu }_B$), the state of matter is in the form of quarks and gluons, which are no longer confined within hadrons. This deconfined state of matter is known as the Quark-Gluon Plasma (QGP). The goal of relativistic heavy-ion collision experiments is to create such a hot and dense state of matter and study its properties. Measurements of identified particle spectra in Au+Au collisions provide information on the bulk properties, such as integrated yield ($dN/dy$), average transverse momenta ($⟨p_T⟩$), particle ratios, and freeze-out parameters of the medium produced. The systematic study of bulk properties sheds light on the particle production mechanism in these collisions. Also, the centrality dependence of the freeze-out parameters provides an opportunity to explore the QCD phase diagram. In this talk, we will present the transverse momentum spectra of identified hadrons (${\pi }^{\pm }$, $K^{\pm }$, $p$, and $\bar{p}$) at mid-rapidity ($|y|<0.1$) in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=54.4$ GeV. The centrality dependence of $dN/dy$, particle ratios, and kinetic freeze-out parameters will also be presented, and their physics implications will be discussed. In addition, we will compare our results with previously published results at other collision energies.

   nucl-exhep-exhep-phSpringer Proc.Phys.(2024)·0 citations
4. 04*

   Hard probes in isobar collisions as a probe of the neutron skin

   Wilke van der Schee🇨🇭 · Yen-Jie Lee🇺🇸 · Govert Nijs🇺🇸 · Yi Chen🇺🇸

   We present an estimate of the yield of hard probes expected for collisions of the isobars ${}_{44}^{96}$Ru and ${}_{40}^{96}$Zr at collision energies reachable at RHIC and the LHC\@. These yields are proportional to the number of binary nucleon-nucleon interactions, which is characteristically different due to the presence of the large neutron skin in ${}_{40}^{96}$Zr. This provides an independent opportunity to measure the difference between the neutron skin of ${}_{44}^{96}$Ru and ${}_{40}^{96}$Zr, which can provide an important constraint on the Equation of State of cold neutron-rich matter.

   ↳ nucl-thhep-phnucl-exPLB(2024)·12 citations
5. 05*

   Atomic number estimation of dual energy cargo radiographs using a semiempirical transparency model

   Peter Lalor · Areg Danagoulian

   Dual energy cargo inspection systems are sensitive to both the area density and the atomic number of an imaged container due to the $Z$ dependence of photon attenuation. The ability to identify cargo contents by their atomic number enables improved detection capabilities of illicit materials. This work introduces a novel method for atomic number reconstruction by minimizing the chi-squared error between measured transparency values and a semiempirical transparency model. This method is tested using two Geant4 Monte Carlo simulated radiographic phantoms, demonstrating the ability to obtain accurate material predictions on noisy input images, even in the presence of shielding. Furthermore, we provide a simple procedure for porting this method to a commercial system, requiring an approximate model of the scanner's beam spectra and detector response, along with only three calibration measurements.

   ↳ eess.IVnucl-exNucl.Instrum.Meth.A(2024)·1 citation
6. 06*

   Spin polarization of heavy quarks in matter: predictions from effective field theories

   Sourendu Gupta🇮🇳

   The spin polarization of heavy quarks in heavy-ion collisions at the LHC is estimated from effective field theories (EFTs). One EFT is similar to the HQET used at zero temperature. This gives a coupling of the heavy quark spin to colour and electromagnetic fields in heavy-ion collisions. The second EFT describes the interaction of heavy quarks and hydrodynamic modes, and gives the coupling between the heavy quark spin and the local vorticity of the fireball. Using these, we find that the measurement of polarization of the heavy quark from small to moderate p_T at the LHC is predicted with a single free parameter proportional to the vorticity. As a result, the heavy quark polarization is the same whether it is derived from the spin alignment of heavy vector mesons or the polarization of heavy baryons. We also predict that the parameter does not differ much between charm and bottom quarks.

   ↳ hep-phhep-exnucl-exnucl-th1 citation
7. 07*

   A Few-Degree Calorimeter for the future Electron-Ion Collider

   Miguel Arratia🇺🇸 · Ryan Milton🇺🇸 · Sebouh J. Paul🇺🇸 · Barak Schmookler🇺🇸 · Weibin Zhang🇺🇸

   Measuring the region $0.1<Q^2<1.0$ GeV${}^2$ is essential to support searches for gluon saturation at the future Electron-Ion Collider. Recent studies have revealed that covering this region at the highest beam energies is not feasible with current detector designs, resulting in the so-called $Q^2$ gap. In this work, we present a design for the Few-Degree Calorimeter (FDC), which addresses this issue. The FDC uses SiPM-on-tile technology with tungsten absorber and covers the range of $-4.6<\eta <-3.6$. It offers fine transverse and longitudinal granularity, along with excellent time resolution, enabling standalone electron tagging. Our design represents the first concrete solution to bridge the $Q^2$ gap at the EIC.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2024)·4 citations
8. 08*

   Thermal conductivity of evolving quark-gluon plasma in the presence of a time-varying magnetic field

   Kamaljeet Singh🇮🇳 · Jayanta Dey🇮🇳 · Raghunath Sahoo🇮🇳

   The effect of the temperature evolution of QGP on its thermal conductivity and elliptic flow is investigated here in the presence of a time-varying magnetic field. Thermal conductivity plays a vital role in the cooling rate of the medium or its temperature evolution. The magnetic field produced during the early stages of (non-central) heavy-ion collisions decays with time, where electrical conductivity plays a significant role. As the medium expands, the electrical and thermal properties change, reflecting the effect in various observables. In this study, we have calculated the thermal conductivity of the QGP medium, incorporating the effects of temperature and magnetic field evolution. We discovered that conductivity significantly depends on the cooling rate, and its value increases due to temperature evolution. Furthermore, the influence of these evolutions on the elliptic flow coefficient is measured, and elliptic flow decreases due to the evolution. We also extend our study for the case of Gubser flow, where, along with the longitudinal Bjorken expansion, the radially transverse expansion is also present.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2024)·17 citations
9. 09*

   Singlet Deuteron, Dineutron and Neutral Nuclei

   S.B. Borzakov🇷🇺

   The existence of the dineutron was predicted over 70 years ago. At present, a number of experimental works confirm this assumption. By virtue of the principle of isotopic invariance, a singlet deuteron must also exist. The possibility of describing the neutron-proton interaction in the state at low energies as the excitation of a quasi-stationary level (singlet deuteron) lying below the deuteron decay threshold is discussed. The position, neutron and radiative widths of the level are determined by the scattering length, the effective radius, and the cross section for the radiative capture of neutrons by protons. Experiments to search for this level are discussed. The discovery of the singlet deuteron would be confirmation of the existence of the dineutron.

   ↳ nucl-thnucl-ex0 citations
10. 10*

    Measurement of the high energy $\gamma$-rays from heavy ion reactions using Čerenkov detector

    Dawei Si · Yan Zhou · Sheng Xiao · Zhigang Xiao

    The energetic bremsstrahlung photons up to 100 MeV produced in heavy ion collisions can be used as a sensitive probe to the short range correlation in atomic nuclei. The energy of the $\gamma$-rays can be measured by collecting the Čerenkov light in medium induced by the fast electrons generated in Compton scattering or electromagnetic shower of the incident $\gamma$ ray. Two types of detectors, based on pure water and lead glass as the sensitive material respectively, are designed for the above purpose. The $\gamma$ response and optical photon propagation in detectors have been simulated based on the electromagnetic and optical processes in Geant4. The inherent energy resolution of $0.022+0.51/E_{\gamma }^{1/2}$ for water and $0.002+0.45/E_{\gamma }^{1/2}$ for lead glass are obtained. The geometry size of lead glass and water are optimized at $30\times 30\times 30$ cm${}^3$ and $60\times 60\times 120$ cm${}^3$, respectively, for detecting high energy $\gamma$-rays at 160 MeV. Hough transform method has been applied to reconstruct the direction of the incident $\gamma$-rays, giving the ability to distinguish experimentally the high-energy $\gamma$ rays produced in the reactions on the target from the random background cosmic ray muons.

    ↳ physics.ins-detnucl-exNucl.Sci.Tech.(2024)·7 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.