Tue·Aug 7, 2018Tuesday·August 7, 2018

1. 01*

   Study of relativistic charged particles production in ^{84}Kr$_{36}+Em interaction at around 1 A GeV with wounded nucleon model

   N. Marimuthu · V. Singh · S. S. R. Inbanathan

   This article is focused on the multiplicity and probability distribution of the emitted charged pions <N_{\pi}> for interaction of ^{84}Kr_{36} projectile with nuclear emulsion targets at kinetic energy 1 GeV per nucleon. In the wounded nucleon model frame work, we have calculated the total number of wounded nucleons (W) and total number of interactions ({\nu}). The obtained results revealed that the average multiplicity of the charged pions <N_{\pi}> is dependent on the projectile and target mass. The calculated values of the wounded nucleons (W) and total number of interactions ({\nu}) shows strong dependence on the mass of the colliding nuclei. The emission rate of mean multiplicity of the <N_{s}> and <N_{\pi}> increases with increasing the total number of wounded nucleons (W) and total number of interactions ({\nu}). The mean multiplicity value of <N_{s}> and <N_{\pi}> linearly increases with increasing the projectile mass number (A_{P}) and independent of the incident energy.

   nucl-exnucl-thIJMPE(2019)·14 citations
2. 02*

   First search for $2\epsilon$ and $\epsilon {\beta }^{+}$ decay of ${}^{162}$Er and new limit on $2{\beta }^{-}$ decay of ${}^{170}$Er to the first excited level of ${}^{170}$Yb

   P. Belli🇮🇹 · R. Bernabei🇮🇹 · R.S. Boiko🇺🇦 · F. Cappella🇮🇹 · V. Caracciolo🇮🇹 · R. Cerulli🇮🇹 · F.A. Danevich🇺🇦 · A. Incicchitti🇮🇹 · B.N. Kropivyansky🇺🇦 · M. Laubenstein🇮🇹 · S. Nisi🇮🇹 · D.V. Poda🇺🇦 · O.G. Polischuk🇺🇦 · V.I. Tretyak🇺🇦

   The first search for double electron capture ($2\epsilon$) and electron capture with positron emission ($\epsilon {\beta }^{+}$) of ${}^{162}$Er to the ground state and to several excited levels of ${}^{162}$Dy was realized with 326 g of highly purified erbium oxide. The sample was measured over 1934 h by the ultra-low background HP Ge $\gamma$ spectrometer GeCris (465 cm${}^3$) at the Gran Sasso underground laboratory. No effect was observed, the half-life limits were estimated at the level of $\lim T_{1/2}\sim 10^{15}-10^{18}$ yr. A possible resonant $0\nu K{L}_1$ capture in ${}^{162}$Er to the $2^{+}$ 1782.7 keV excited state of ${}^{162}$Dy is restricted as $T_{1/2}\ge 5.0\times 10^{17}$ yr at 90% C.L. A new improved half-life limit $T_{1/2}\ge 4.1\times 10^{17}$ yr was set on the $2{\beta }^{-}$ decay of ${}^{170}$Er to the $2^{+}$ 84.3 keV first excited state of ${}^{170}$Yb.

   nucl-exJ.Phys.G(2018)·9 citations
3. 03*

   Measurement of the analyzing powers in pd elastic and pn quasi-elastic scattering at small angles

   S.Barsov🇷🇺 · Z.Bagdasarian🇩🇪 · S.Dymov🇩🇪 · R.Gebel🇩🇪 · M.Hartmann🇩🇪 · A.Kacharava🇩🇪 · I.Keshelashvili🇨🇭 · A.Khoukaz🇩🇪 · V.Komarov🇷🇺 · P.Kulessa🇵🇱 · A.Kulikov🇷🇺 · A.Lehrach🇩🇪 and 21 other authors

   The analyzing powers in proton-deuteron elastic and proton-neutron quasi-elastic scattering have been measured at small angles using a polarized proton beam at the COSY storage ring incident on an unpolarized deuterium target. The data were taken at 796MeV and five higher energies from 1600MeV to 2400MeV. The analyzing power in pd elastic scattering was studied by detecting the low energy recoil deuteron in telescopes placed symmetrically in the COSY plane to the left and right of the beam whereas for pn quasi-elastic scattering a low energy proton was registered in one of the telescopes in coincidence with a fast scattered proton measured in the ANKE magnetic spectrometer. Though the experiment explores new domains, the results are consistent with the limited published information.

   nucl-exnucl-thEPJA(2018)·3 citations
4. 04*

   Heavy-ion collisions - hot QCD in a lab

   Mateusz Ploskon🇺🇸

   High-energy heavy-ion collisions provide a unique opportunity to study the properties of the hot and dense strongly-interacting system composed of deconfined quarks and gluons -- the quark-gluon plasma (QGP) -- in laboratory conditions. The formation of a QGP is predicted by lattice QCD calculations as a crossover transition from hadronic matter (at zero baryochemical potential) and is expected to take place once the system temperature reaches values above 155 MeV and/or the energy density above $0.5\mathrm{GeV}/{\mathrm{fm}}^3$. The nature of such a strongly coupled QGP has been linked to the early Universe at some microseconds after the Big Bang. To characterize the physical properties of the short-lived matter (lifetime of about $10\mathrm{fm}/c$) experimental studies at Relativistic Heavy-Ion Collider and the Large Hadron collider use auto-generated probes, such as high-energy partons created early in the hadronic collisions, thermally emitted photons, and a set of particle correlations that are sensitive to the collective expansion and the dynamics of the system. The lectures briefly introduced some of the experimental techniques and provided a glimpse at some of the results.

   ↳ hep-exhep-phnucl-exnucl-th10 citations
5. 05*

   Radial Flow and Differential Freeze-out in Proton-Proton Collisions at $\sqrt{s}=7$ TeV at the LHC

   Arvind Khuntia🇮🇳 · Himanshu Sharma🇮🇳 · Swatantra Kumar Tiwari🇮🇳 · Raghunath Sahoo🇮🇳 · Jean Cleymans🇿🇦

   We analyse the transverse momentum ($p_{\mathrm{T}}$)-spectra as a function of charged-particle multiplicity at midrapidity ($|y|<0.5$) for various identified particles such as ${\pi }^{\pm }$, $K^{\pm }$, $K_S^0$, $p+\overline{p}$, $\varphi$, $K^{\ast 0}+\overline{K^{\ast 0}}$, and $\Lambda$ + $\bar{\Lambda }$ in proton-proton collisions at $\sqrt{s}$ = 7 TeV using Boltzmann-Gibbs Blast Wave (BGBW) model and thermodynamically consistent Tsallis distribution function. We obtain the multiplicity dependent kinetic freeze-out temperature ($T_{\mathrm{kin}}$) and radial flow ($\beta$) of various particles after fitting the $p_{\mathrm{T}}$-distribution with BGBW model. Here, $T_{\mathrm{kin}}$ exhibits mild dependence on multiplicity class while $\beta$ shows almost independent behaviour. The information regarding Tsallis temperature and the non-extensivity parameter ($q$) are drawn by fitting the $p_{\mathrm{T}}$-spectra with Tsallis distribution function. The extracted parameters of these particles are studied as a function of charged particle multiplicity density ($d{N}_{ch}/d\eta$). In addition to this, we also study these parameters as a function of particle mass to observe any possible mass ordering. All the identified hadrons show a mass ordering in temperature, non-extensive parameter and also a strong dependence on multiplicity classes, except the lighter particles. It is observed that as the particle multiplicity increases, the $q$-parameter approaches to Boltzmann-Gibbs value, hence a conclusion can be drawn that system tends to thermal equilibrium. The observations are consistent with a differential freeze-out scenario of the produced particles.

   ↳ hep-phhep-exnucl-exnucl-thEPJA(2019)·48 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.