Wed·Jan 30, 2019Wednesday·January 30, 2019

1. 01*

   Probing nucleon's spin structures with polarized Drell-Yan in the Fermilab SpinQuest experiment

   Andrew Chen🇺🇸 · J.C. Peng🇺🇸 · H. Leung🇺🇸 · M. Tian🇺🇸 · N. Makins🇺🇸 · M. Brooks🇺🇸 · A. Klein🇺🇸 · D. Kleinjan🇺🇸 · K. Liu🇺🇸 · M. McCumber🇺🇸 · P. McGaughey🇺🇸 · J. Miraal-Martinez🇺🇸 and 42 other authors

   Although the proton was discovered about 100 years ago, its spin structure still remains a mystery. Recent studies suggest that the orbital angular momentum of sea quarks could significantly contribute to the proton's spin. The SeaQuest experiment, which recently completed data collection, probed the unpolarized light quark sea distributions of the proton using the Drell-Yan process. Its successor, the SpinQuest (E1039), will access the $\bar{u}$ and $\bar{d}$ Sivers functions using polarized NH${}_3$ and ND${}_3$ targets. A non-zero Sivers asymmetry, observed in SpinQuest, would be a strong indication of non-zero sea-quark orbital angular momentum. The SpinQuest experiment can also probe the sea quark's transversity distribution, which is relevant for the determination of proton's tensor charge. Recent study suggests that sea-quarks might contribute significantly to deuteron's tensor polarized structure functions. This can be further probed in SpinQuest using tensor polarized ND${}_3$ target. The current status and future plan of the experiment are presented.

   nucl-exnucl-thPoS(2019)·23 citations
2. 02*

   Measurement of 73Ge(n,g) cross sections and implications for stellar nucleosynthesis

   Claudia Lederer-Woods (and the n_TOF Collaboration)

   73Ge(n,g) cross sections were measured at the neutron time-of-flight facility n_TOF at CERN up to neutron energies of 300 keV, providing for the first time experimental data above 8 keV. Results indicate that the stellar cross section at kT = 30 keV is 1.5 to 1.7 times higher than most theoretical predictions. The new cross sections result in a substantial decrease of 73Ge produced in stars, which would explain the low isotopic abundance of 73Ge in the solar system.

   nucl-exPLB(2019)·13 citations
3. 03*

   Dijet azimuthal correlations and conditional yields in $pp$ and $p$+Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV with the ATLAS detector

   ATLAS Collaboration

   This paper presents a measurement of forward-forward and forward-central dijet azimuthal angular correlations and conditional yields in proton-proton ($pp$) and proton-lead ($p$+Pb) collisions as a probe of the nuclear gluon density in regions where the fraction of the average momentum per nucleon carried by the parton entering the hard scattering is low. In these regions, gluon saturation can modify the rapidly increasing parton distribution function of the gluon. The analysis utilizes 25 pb${}^{-1}$ of $pp$ data and 360 $\mu {\mathrm{b}}^{-1}$ of $p$+Pb data, both at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV, collected in 2015 and 2016, respectively, with the ATLAS detector at the LHC. The measurement is performed in the center-of-mass frame of the nucleon-nucleon system in the rapidity range between $-$4.0 and 4.0 using the two highest transverse momentum jets in each event, with the highest transverse momentum jet restricted to the forward rapidity range. No significant broadening of azimuthal angular correlations is observed for forward-forward or forward-central dijets in $p$+Pb compared to $pp$ collisions. For forward-forward jet pairs in the proton-going direction, the ratio of conditional yields in $p$+Pb collisions to those in $pp$ collisions is suppressed by approximately 20%, with no significant dependence on the transverse momentum of the dijet system. No modification of conditional yields is observed for forward-central dijets.

   nucl-exhep-exPRC(2019)·57 citations
4. 04*

   On the elliptic flow of heavy quarkonia in $pA$ collisions

   Cheng Zhang🇨🇳 · Cyrille Marquet🇫🇷 · Guang-You Qin🇨🇳 · Shu-Yi Wei🇫🇷 · Bo-Wen Xiao🇨🇳

   Using the dilute-dense factorization in the Color Glass Condensate framework, we investigate the azimuthal angular correlation between a heavy quarkonium and a charged light hadron in proton-nucleus collisions. We extract the second harmonic $v_2$, commonly known as the elliptic flow, with the light hadron as the reference. This particular azimuthal angular correlation between a heavy meson and a light hadron has first been measured at the LHC recently. The experimental results indicate that the elliptic flows for heavy-flavor mesons ($J/\psi$ and $D^0$) are almost as large as those for light hadrons. Our calculation demonstrates that this result can be naturally interpreted as an initial state effect due to the interaction between the incoming partons from the proton and the dense gluons inside the target nucleus. Since the heavy quarkonium $v_2$ exhibits a weak mass dependence according to our calculation, we predict that the heavy quarkonium ${\rm Y}$ should have a similar elliptic flow as compared to that of the $J/\psi$, which can be tested in future measurements.

   ↳ hep-phnucl-exnucl-thPRL(2019)·62 citations
5. 05*

   Resolution enhancement with light/heat decorrelation in CUPID-0 bolometric detector

   M. Beretta🇮🇹 · L. Cardani🇮🇹 · N. Casali🇮🇹 · L. Gironi🇮🇹 · L. Pagnanini🇮🇹 · F. Bellini🇮🇹 · C. Brofferio🇮🇹 · D. Chiesa🇮🇹 · S. Capelli🇮🇹 · S. Di Domizio🇮🇹 · L. Pattavina🇮🇹 · M. Pavan🇮🇹 and 6 other authors

   The CUPID-0 experiment searches for neutrinoless double beta decay ($0\nu \beta \beta$) using the first array of enriched Zn${}^{82}$Se scintillating bolometers with double (heat and light) read-out. To further enhance the CUPID-0 detector performances, the heat-light correlation has been exploited to improve the energy resolution. Different decorrelation algorithms have been studied and the best result is the average reduction of the full width at half maximum (FWHM) energy resolution to $(90.5\pm 0.6)\%$ of its original value , corresponding to a change from $\text{FWHM}=(20.7\pm 0.5)\text{keV}$ to $\text{FWHM}=(18.7\pm 0.5)\text{keV}$ at the 2615 keV $\gamma$ line.

   ↳ physics.ins-detnucl-exJINST(2019)·9 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.