Tue·Jun 16, 2020Tuesday·June 16, 2020

1. 01*

   Measurement of the azimuthal anisotropy of ${\rm Y}$(1S) and ${\rm Y}$(2S) mesons in PbPb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV

   CMS Collaboration

   The second-order Fourier coefficients ($v_2$) characterizing the azimuthal distribution of ${\rm Y}$(1S) and ${\rm Y}$(2S) mesons arising from PbPb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV are studied. The ${\rm Y}$ mesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The data set corresponds to an integrated luminosity of 1.7 nb${}^{-1}$. The scalar product method is used to extract the $v_2$ coefficients of the azimuthal distribution. Results are reported for the rapidity range $|y|$ $<$ 2.4, with the transverse momentum 0 $<$ $p_{\mathrm{T}}$ $<$ 50 GeV/$c$, and in three centrality ranges of 10-30%, 30-50% and 50-90%. In contrast to the J/$\psi$ mesons, the measured $v_2$ values for the ${\rm Y}$ mesons are found to be consistent with zero.

   ↳ hep-exnucl-exPLB(2021)·75 citations
2. 02*

   Analytic insights on the information content of new observables

   Wei-Chia Chen · J. Piekarewicz🇺🇸

   Uncertainty quantification has emerged as a rapidly growing field in nuclear science. Theoretical predictions of physical observables often involve extrapolations to regions that are poorly constrained by laboratory experiments and astrophysical observations. Without properly quantified theoretical errors, such model predictions are of limited value. Also, one often deals with theoretical constructs that involve fundamental quantities that are not accessible to experiment or observation. Particularly relevant in this context is the pressure of pure neutron matter. In this contribution we develop an analytic framework to answer the question of "How can new data reduce uncertainties of current theoretical models?" [P.-G. Reinhard and W. Nazarewicz, Phys. Rev. C81, 051303(R) (2010)]. Simple and insightful expressions are obtained to quantify the impact of one or two new observables on theoretical uncertainties in two critical quantities: the slope of the symmetry energy at saturation density and the pressure of pure neutron matter at twice nuclear matter saturation density.

   ↳ nucl-thastro-ph.SRnucl-exPRC(2020)·2 citations
3. 03*

   The FAIR Phase 0 program of the CBM TOF

   Ingo Deppner🇩🇪 · Norbert Herrmann🇩🇪

   In order to provide particle identification (PID) of charged hadrons at the future high-rate Compressed Baryonic Matter (CBM) experiment the TOF group has developed a large-area Time-of-Flight (ToF) wall equipped with Multi-gap Resistive Plate Chambers (MRPC) capable to operate at incident particle fluxes of up to 30 kHz/cm${}^2$. Prior to its destined operation at the Facility for Antiproton and Ion Research (FAIR) - starting in 2025 - this high-rate timing MRPC technology will be used for physics research at two scientific pillars of the FAIR Phase-0 program: the end-cap TOF upgrade of the STAR experiment at RHIC and the mTOF wall of the mCBM experiment at SIS18. At STAR, the fixed-target program of the Beam Energy Scan II (BES-II) will rely on 108 CBM MRPC detectors for forward PID at trigger rates of up to 2 kHz. At mCBM, high-performance benchmark runs of Lambda-baryon production at top SIS18 energies and CBM design interaction rates of 10 MHz will become feasible with a PID backbone consisting of 25 CBM MRPC detectors. Apart from the physics perspective, these pre-FAIR involvements will help gathering experience in operating the final CBM TOF wall comprising about 1500 MRPC detectors and 110,000 readout channels. The status of the FAIR phase 0 program will be discussed.

   ↳ physics.ins-detnucl-exJINST(2020)·13 citations
4. 04*

   Determining the nuclear neutron distribution from Coherent Elastic neutrino-Nucleus Scattering: current results and future prospects

   Pilar Coloma🇪🇸 · Ivan Esteban🇪🇸 · M.C. Gonzalez-Garcia🇪🇸 · Javier Menendez🇪🇸

   Coherent elastic neutrino-nucleus scattering (CE$\nu$NS), a process recently measured for the first time at ORNL's Spallation Neutron Source, is directly sensitive to the weak form factor of the nucleus. The European Spallation Source (ESS), presently under construction, will generate the most intense pulsed neutrino flux suitable for the detection of CE$\nu$NS. In this paper we quantify its potential to determine the root mean square radius of the point-neutron distribution, for a variety of target nuclei and a suite of detectors. To put our results in context we also derive, for the first time, a constraint on this parameter from the analysis of the energy and timing data of the CsI detector at the COHERENT experiment.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2020)·54 citations
5. 05*

   Forward doubly-virtual Compton scattering off the nucleon in chiral perturbation theory: II. Spin polarizabilities and moments of polarized structure functions

   Jose Manuel Alarcón (U. Complutense de Madrid & IPARCOS)🇪🇸 · Franziska Hagelstein (AEC Bern)🇨🇭 · Vadim Lensky🇩🇪 · Vladimir Pascalutsa (JGU Mainz)🇩🇪

   We examine the polarized doubly-virtual Compton scattering (VVCS) off the nucleon using chiral perturbation theory ($\chi$PT). The polarized VVCS contains a wealth of information on the spin structure of the nucleon which is relevant to the calculation of the two-photon-exchange effects in atomic spectroscopy and electron scattering. We report on a complete next-to-leading-order (NLO) calculation of the polarized VVCS amplitudes $S_1(\nu ,Q^2)$ and $S_2(\nu ,Q^2)$, and the corresponding polarized spin structure functions $g_1(x,Q^2)$ and $g_2(x,Q^2)$. Our results for the moments of polarized structure functions, partially related to different spin polarizabilities, are compared to other theoretical predictions and "data-driven" evaluations, as well as to the recent Jefferson Lab measurements. By expanding the results in powers of the inverse nucleon mass, we reproduce the known "heavy-baryon" expressions. This serves as a check of our calculation, as well as demonstrates the differences between the manifestly Lorentz-invariant baryon $\chi$PT (B$\chi$PT) and heavy-baryon (HB$\chi$PT) frameworks.

   ↳ hep-phhep-latnucl-exnucl-th+1PRD(2020)·23 citations
6. 06*

   Optimization and first tests of the experimental setup to investigate the double-polarized DD-fusion reactions

   A. Solovev🇷🇺 · A. Andreyanov · L. Barion🇮🇹 · G. Ciullo🇮🇹 · R. Engels · V. Fotyev · K. Ivshin🇷🇺 · L. Kochenda🇷🇺 · P. Kravchenko · P. Kravtsov🇷🇺 · V. Larionov · A. Rozhdestvensky and 5 other authors

   The study of DD reactions, especially with polarized reactants, helps for better understanding of the processes taking place in nuclear astrophysics and fusion reactors. At PNPI Gatchina, Russia, the PolFusion experiment with crossing of two polarized beams, i.e. a deuteron and a deuterium beam, is able to measure angular distributions of the differential cross section and, therefore, the spin-correlations coefficients with different combinations of the adjustable nuclear polarization of both beams with a center-of-mass energy between 10 to 100 keV. Some improvements and fine-tuning of the polarized ion source are performed and presented. The atomic beam source for the jet target has been modified as well. An unpolarized experiment with a 10 keV ion beam and heavy water vapor as a target has been carried out with successful registration of the fusion products

   ↳ physics.ins-detnucl-exJINST(2020)·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.