Wed·May 3, 2017Wednesday·May 3, 2017

1. 01*

   The search for neutron-antineutron oscillations at the Sudbury Neutrino Observatory

   SNO Collaboration: B. Aharmim🇨🇦 · S. N. Ahmed🇨🇦 · A. E. Anthony🇺🇸 · N. Barros🇵🇹 · E. W. Beier🇺🇸 · A. Bellerive🇨🇦 · B. Beltran🇨🇦 · M. Bergevin🇺🇸 · S. D. Biller🇬🇧 · K. Boudjemline🇨🇦 · M. G. Boulay🇨🇦 · B. Cai🇨🇦 and 112 other authors

   Tests on $B-L$ symmetry breaking models are important probes to search for new physics. One proposed model with $\Delta (B-L)=2$ involves the oscillations of a neutron to an antineutron. In this paper a new limit on this process is derived for the data acquired from all three operational phases of the Sudbury Neutrino Observatory experiment. The search was concentrated in oscillations occurring within the deuteron, and 23 events are observed against a background expectation of 30.5 events. These translate to a lower limit on the nuclear lifetime of $1.48\times 10^{31}$ years at 90% confidence level (CL) when no restriction is placed on the signal likelihood space (unbounded). Alternatively, a lower limit on the nuclear lifetime was found to be $1.18\times 10^{31}$ years at 90% CL when the signal was forced into a positive likelihood space (bounded). Values for the free oscillation time derived from various models are also provided in this article. This is the first search for neutron-antineutron oscillation with the deuteron as a target.

   ↳ hep-exnucl-exphysics.ins-detPRD(2017)·65 citations
2. 02*

   Multiparticle collectivity from initial state correlations in high energy proton-nucleus collisions

   Kevin Dusling🇺🇸 · Mark Mace🇺🇸 · Raju Venugopalan🇺🇸

   Qualitative features of multiparticle correlations in light-heavy ion ($p+A$) collisions at RHIC and LHC are reproduced in a simple initial state model of partons in the projectile coherently scattering off localized domains of color charge in the heavy nuclear target. These include i) the ordering of the magnitudes of the azimuthal angle $n$th Fourier harmonics of two-particle correlations $v_n\{2\}$, ii) the energy and transverse momentum dependence of the four-particle Fourier harmonic $v_2\{4\}$, and iii) the energy dependence of four-particle symmetric cumulants measuring correlations between different Fourier harmonics. Similar patterns are seen in an Abelian version of the model, where we observe $v_2\{2\}>v_2\{4\}\approx v_2\{6\}\approx v_2\{8\}$ of two, four, six, and eight particle correlations. While such patterns are often interpreted as signatures of collectivity arising from hydrodynamic flow, our results provide an alternative description of the multiparticle correlations seen in $p+A$ collisions.

   ↳ hep-phnucl-exnucl-thPRL(2018)·100 citations
3. 03*

   Coherent J/$\psi$ photoproduction in hadronic heavy-ion collisions

   W. Zha🇨🇳 · S.R. Klein🇺🇸 · R. Ma🇺🇸 · L. Ruan🇺🇸 · T. Todoroki🇺🇸 · Z. Tang🇨🇳 · Z. Xu🇨🇳 · C. Yang🇨🇳 · Q. Yang🇨🇳 · S. Yang🇺🇸

   A significant excess of J/$\psi$ yield at very low transverse momentum ($p_T<0.3$ GeV/c) was observed by the ALICE and STAR collaborations in peripheral A+A collisions, which points to evidence of coherent photoproduction of J/$\psi$ in violent hadronic interactions. Theoretically, the photoproduction of J$/\psi$ in hadronic collisions raises questions about how spectator and non-spectator nucleons participate in the coherent reaction. For the first time, we argue that the strong interactions in the overlapping region of incoming nuclei may disturb the coherent production, leaving room for different coupling assumptions. Furthermore, first considerations of the destructive interference between photoproduction on ions moving in opposite directions in hadronic heavy-ion collisions are included. This letter presents calculations of J$/\psi$ production from coherent photon-nucleus ($\gamma +A\to \text{J}/\psi +A$) interactions in hadronic A+A collisions at RHIC and LHC energies with both nucleus and spectator coupling hypotheses. The coherent J/$\psi$ yield as a function of centrality and differential distributions as a function of transverse momentum, azimuthal angle and rapidity in different centrality bins are shown and found to be significantly different for different coupling scenarios, calling for future experimental measurements.

   ↳ nucl-thhep-phnucl-exPRC(2018)·78 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.