Thu·Nov 11, 2021Thursday·November 11, 2021

1. 01*

   Experimental Search for Neutron to Mirror Neutron Oscillations as an Explanation of the Neutron Lifetime Anomaly

   L. J. Broussard🇺🇸 · J. L. Barrow🇺🇸 · L. DeBeer-Schmitt🇺🇸 · T. Dennis🇺🇸 · M. R. Fitzsimmons🇺🇸 · M. J. Frost🇺🇸 · C. E. Gilbert🇺🇸 · F. M. Gonzalez🇺🇸 · L. Heilbronn🇺🇸 · E. B. Iverson🇺🇸 · A. Johnston🇺🇸 · Y. Kamyshkov🇺🇸 and 6 other authors

   An unexplained $>4\sigma$ discrepancy persists between "beam" and "bottle" measurements of the neutron lifetime. A new model proposed that conversions of neutrons $n$ into mirror neutrons $n^{\prime }$, part of a dark mirror sector, can increase the apparent neutron lifetime by $1\%$ via a small mass splitting $\Delta m$ between $n$ and $n^{\prime }$ inside the 4.6 T magnetic field of the National Institute of Standards and Technology Beam Lifetime experiment. A search for neutron conversions in a 6.6 T magnetic field was performed at the Spallation Neutron Source which excludes this explanation for the neutron lifetime discrepancy.

   nucl-exhep-exPRL(2022)·43 citations
2. 02*

   New results on the modification of jet structure in Heavy Ion collisions

   Helena Santos (on behalf of the ALICE, ATLAS, and CMS Collabrations)🇵🇹

   These proceedings report recent studies performed by the ALICE, ATLAS and CMS experiments on jet substructure in pp and Pb+Pb collisions at 5.02 TeV. The dependence of the modification of the jet shape on the dijet transverse moment um asymmetry is presented. Measurements of particles recoiling against the Z boson without being constrained to jet cone delimitations are shown. Fully-corrected measurements of the N-subjettiness within anti-kt R = 0.4 charged-particle jets are also described.

   nucl-exhep-exPoS(2021)·0 citations
3. 03*

   Systematic study of nuclear effects in $p$$+$Al, $p$$+$Au, $d$$+$Au, and ${}^3$He$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV using ${\pi }^0$ production

   U.A. Acharya · A. Adare · C. Aidala · N.N. Ajitanand · Y. Akiba · H. Al-Bataineh · J. Alexander · M. Alfred · V. Andrieux · A. Angerami · K. Aoki · N. Apadula and 543 other authors

   The PHENIX collaboration presents a systematic study of ${\pi }^0$ production from $p$$+$$p$, $p$$+$Al, $p$$+$Au, $d$$+$Au, and ${}^3$He$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV. Measurements were performed with different centrality selections as well as the total inelastic, 0%--100%, selection for all collision systems. For 0%--100% collisions, the nuclear modification factors, $R_{xA}$, are consistent with unity for $p_T$ above 8 GeV/$c$, but exhibit an enhancement in peripheral collisions and a suppression in central collisions. The enhancement and suppression characteristics are similar for all systems for the same centrality class. It is shown that for high-$p_T$-${\pi }^0$ production, the nucleons in the $d$ and ${}^3$He interact mostly independently with the Au nucleus and that the counter intuitive centrality dependence is likely due to a physical correlation between multiplicity and the presence of a hard scattering process. These observations disfavor models where parton energy loss has a significant contribution to nuclear modifications in small systems. Nuclear modifications at lower $p_T$ resemble the Cronin effect -- an increase followed by a peak in central or inelastic collisions and a plateau in peripheral collisions. The peak height has a characteristic ordering by system size as $p$$+$Au $>$ $d$$+$Au $>$ ${}^3$He$+$Au $>$ $p$$+$Al. For collisions with Au ions, current calculations based on initial state cold nuclear matter effects result in the opposite order, suggesting the presence of other contributions to nuclear modifications, in particular at lower $p_T$.

   nucl-exhep-exPRC(2022)·38 citations
4. 04*

   Density dependence of symmetry energy and neutron skin thickness revisited using relativistic mean field models with nonlinear couplings

   Chiranjib Mondal🇫🇷

   The correlation between neutron skin-thickness of a neutron-rich nucleus and slope parameter of symmetry energy is assessed as a function of density using relativistic mean field models containing non-linear couplings among different mesons. Models with larger skin were found to probe the slope parameter even at suprasaturation densities, whereas models with smaller skin were observed to be sensitive only at specific subsaturation density, connected to the average density of nuclei. Possible reasons behind this density dependence are explored systematically. These results might be model specific, which need to be reassessed in other type of interactions existing in the literature. Nevertheless, extrapolating the predictions at high densities from models, which are optimized by data at saturation or subsaturation densities, needs to be handled with care.

   ↳ nucl-thastro-ph.HEnucl-exPRC(2022)·6 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.