Thu·May 23, 2019Thursday·May 23, 2019

1. 01*

   K*(892)^0 production in p+p interactions at 158 GeV/c from NA61/SHINE

   A.Tefelska🇵🇱

   The measurement of $K^{\ast }(892{)}^0$ resonance production via its $K^{+}{\pi }^{-}$ decay mode in inelastic p+p collisions at beam momentum 158~GeV/c ($\sqrt{s_{NN}}=17.3$~GeV) is presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The first ever double differential measurements and $p_T$-integrated spectra of $K^{\ast }(892{)}^0$ at beam momenta of 158 GeV/c was done by using the \textit{template} fitting method. The full phase-space yields, mass and width of $K^{\ast }(892{)}^0$ mesons are compared with Hadron Resonance Gas models as well as with world data on p+p and nucleus-nucleus collisions.

   nucl-exPoS(2019)·1 citation
2. 02*

   A fast-switching magnet serving a spallation-driven ultracold neutron source

   S. Ahmed (1)🇨🇦 · E. Altiere (2)🇨🇦 · T. Andalib (1)🇨🇦 · M.J. Barnes (3)🇨🇭 · B. Bell (4 and 5)🇨🇦 · C.P. Bidinosti (6 and 1)🇨🇦 · Y. Bylinsky (4)🇨🇦 · J. Chak (4)🇨🇦 · M. Das (1)🇨🇦 · C.A. Davis (4)🇨🇦 · F. Fischer (4 and 7)🇩🇪 · B. Franke (4)🇨🇦 and 38 other authors

   A fast-switching, high-repetition-rate magnet and power supply have been developed for and operated at TRIUMF, to deliver a proton beam to the new ultracold neutron (UCN) facility. The facility possesses unique operational requirements: a time-averaged beam current of 40~$\mu$A with the ability to switch the beam on or off for several minutes. These requirements are in conflict with the typical operation mode of the TRIUMF cyclotron which delivers nearly continuous beam to multiple users. To enable the creation of the UCN facility, a beam-sharing arrangement with another facility was made. The beam sharing is accomplished by the fast-switching (kicker) magnet which is ramped in 50~$\mu$s to a current of 193~A, held there for approximately 1~ms, then ramped down in the same short period of time. This achieves a 12~mrad deflection which is sufficient to switch the proton beam between the two facilities. The kicker magnet relies on a high-current, low-inductance coil connected to a fast-switching power supply that is based on insulated-gate bipolar transistors (IGBTs). The design and performance of the kicker magnet system and initial beam delivery results are reported.

   ↳ physics.acc-phnucl-exphysics.ins-detPhys.Rev.Accel.Beams(2019)·13 citations
3. 03*

   Hadronization and Charm-Hadron Ratios in Heavy-Ion Collisions

   Min He🇨🇳 · Ralf Rapp🇺🇸

   Understanding the hadronization of the quark-gluon plasma (QGP) remains a challenging problem in the study of strong-interaction matter as produced in ultrarelativistic heavy-ion collisions (URHICs). The large mass of heavy quarks renders them excellent tracers of the color neutralization process of the QGP when they convert into various heavy-flavor (HF) hadrons. We develop a 4-momentum conserving recombination model for HF mesons and baryons that recovers the thermal and chemical equilibrium limits and accounts for space-momentum correlations (SMCs) of heavy quarks with partons of the hydrodynamically expanding QGP, thereby resolving a long-standing problem in quark coalescence models. The SMCs enhance the recombination of fast-moving heavy quarks with high-flow thermal quarks in the outer regions of the fireball. We also improve the hadro-chemistry with "missing" charm-baryon states, previously found to describe the large ${\Lambda }_c/D^0$ ratio observed in proton-proton collisions. Both SMCs and hadro-chemistry, as part of our HF hydro-Langevin-recombination model for the strongly coupled QGP, importantly figure in the description of recent data for the ${\Lambda }_c/D^0$ ratio and $D$-meson elliptic flow in URHICs.

   ↳ nucl-thhep-phnucl-exPRL(2020)·179 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.