Mon·Oct 8, 2018Monday·October 8, 2018

1. 01*

   Second T = 3/2 state in ${}^9$B and the isobaric multiplet mass equation

   N.J. Mukwevho🇿🇦 · B.M. Rebeiro🇿🇦 · D.J. Marín-Lámbarri🇨🇱 · S. Triambak🇿🇦 · P. Adsley🇫🇷 · N.Y. Kheswa🇿🇦 · R. Neveling · L. Pellegri🇿🇦 · V. Pesudo🇪🇸 · F.D. Smit🇿🇦 · E.H. Akakpo · J.W. Brümmer🇿🇦 and 8 other authors

   Recent high-precision mass measurements and shell model calculations~[Phys. Rev. Lett. {\bf 108}, 212501 (2012)] have challenged a longstanding explanation for the requirement of a cubic isobaric multiplet mass equation for the lowest $A=9$ isospin quartet. The conclusions relied upon the choice of the excitation energy for the second $T=3/2$ state in ${}^9$B, which had two conflicting measurements prior to this work. We remeasured the energy of the state using the ${}^9\mathrm{Be}{(}^3\mathrm{He},t)$ reaction and significantly disagree with the most recent measurement. Our result supports the contention that continuum coupling in the most proton-rich member of the quartet is not the predominant reason for the large cubic term required for $A=9$ nuclei.

   nucl-exPRC(2018)·4 citations
2. 02*

   Open charm measurements with the NA61/SHINE experiment at the CERN SPS

   Dag Larsen🇵🇱 · Anastasia Merzlaya (for the NA61/SHINE Collaboration)🇵🇱

   The strong interactions programme of the NA61/SHINE experiment at the CERN SPS has been extended through the use of new silicon Vertex Detector, which allows for reconstructing open charm particles. The detector was designed to identify those particles by means of a precise reconstruction of their primary and secondary vertices. An initial version of the Vertex Detector, called SAVD (Small Acceptance Vertex Detector), was installed end of 2016. It was operated in a Pb+Pb calibration beam time in 2016, and with Xe+La in 2017. A further Pb+Pb beam time is scheduled for late 2018. The first indications of a D${}^0$ peak were observed in the data obtained from the 2016 Pb+Pb run. This work introduces the physics motivation behind the open charm measurements, and the status of the analysis of the collected data on open charm production. Moreover, the plans of future open charm measurements in NA61/SHINE experiment and the related to upgrades of the vertex detector will be discussed.

   nucl-exJ.Phys.Conf.Ser.(2018)·1 citation
3. 03*

   The onsets of deconfinement and fireball of NA61/SHINE

   Dag Larsen (for the NA61/SHINE Collaboration)🇵🇱

   The NA61/SHINE experiment at the CERN SPS is pursuing a rich programme on strong interactions, covering the study of onset of deconfinement and aims to discover the critical point of strongly interacting matter by performing an energy and system-size scan at the full CERN SPS momentum range. These scans of p+p, p+Pb, Be+Be, Ar+Sc and Pb+Pb have been mostly completed with Xe+La last year (more Pb+Pb to to taken this year). Results from the different reactions are now emerging. As a surprise, some measurements did not scale smoothly. In particular, for the ${\mathrm{K}}^{+}/{\text{piup}}^{+}$ ratio, Be+Be collisions behaved similarly to p+p (as superposition of nucleon collisions), while Ar+Sc was closer to Pb+Pb collisions. This step can not be explained by onset of deconfinement, and may indicate that there is also a onset of fireball in relativistic heavy ion collisions. A review of the results as well as possible interpretation will be presented. The theoretical models (SMES, PHSD) describe onset of deconfinement at the heaviest system relatively well. However, no model describes the behaviour of data at previously unmeasured collisions of light and intermediate size ions. The onset of fireball is not described by any model.

   nucl-exEPJ Web Conf.(2019)·3 citations
4. 04*

   Open Charm measurements at the NA61 experiment at CERN SPS

   Dag Larsen🇵🇱 · Anastasia Merzlaya (for the NA61/SHINE Collaboration)🇵🇱

   The strong interactions programme of the NA61/SHINE experiment at CERN SPS has been extended through the use of new silicon Vertex Detector which provides precise measurements of exotic particles with short lifetime. The detector was designed to meet the challenges of primary and secondary vertexes reconstruction at high spatial resolution. An initial version of the Vertex Detector called SAVD (Small Acceptance Vertex Detector) was installed last end of 2016, and data was from Pb+Pb collisions was collected in 2016, for Xe+La in 2017, as well as further Pb+Pb collisions this year. First indication of a D${}^0$ peak at SPS energies has been observed. The physics motivation behind the open charm measurements will be discussed, as well as the analysis of collected data on open charm production and the future plans of open charm measurements in NA61/SHINE experiment related to the upgraded version of the vertex detector.

   nucl-exEPJ Web Conf.(2018)·0 citations
5. 05*

   Open charm measurements at CERN SPS energies with the new Vertex Detector of the NA61/SHINE experiment

   Anastasia Merzlaya (for the NA61/SHINE Collaboration)🇵🇱

   The study of open charm meson production provides an efficient tool for detailed investigations of the properties of hot and dense matter formed in nucleus-nucleus collisions. The interpretation of the existing data from the CERN SPS suffers from a lack of knowledge on the total charm production rate. To overcome this limitation the heavy-ion programme of the NA61/SHINE experiment at CERN SPS has been expanded to allow for precise measurements of particles with a short lifetime. A new Small Acceptance Vertex Detector (SAVD) was designed and constructed to meet the challenges of open charm measurements in nucleus-nucleus collisions. SAVD was installed in December 2016 for data taking with Pb+Pb collisions at 150$A$ GeV/c. An exploratory set of collected data allowed to validate the general concept of the $D^0$ mesons detection via its $D^0\to {\pi }^{+}+K^{-}$ decay channel and delivered the first direct observation of open charm at SPS energies. In October and November of 2017 a large statistic data set has been taken for Xe+La at 150$A$, 75$A$, and 40$A$ GeV/c, these data are currently under intense analysis. The physics motivation behind the open charm measurements at the SPS energies will be discussed. Moreover, the concept of the SAVD hardware and status of the analysis will be shown. Also, the future plans of open charm measurements in the NA61/SHINE experiment related to the upgraded Vertex Detector will be presented.

   nucl-exEPJ Web Conf.(2019)·0 citations
6. 06*

   Latest results from the NA61/SHINE experiment

   Dag Larsen (for the NA61/SHINE Collaboration)🇵🇱

   The NA61/SHINE experiment at the CERN Super Proton Synchrotron is pursuing a rich programme on strong interactions, which covers the study of the onset of deconfinement and aims to discover the critical point of strongly interacting matter by performing an energy and system-size scan over the full CERN SPS beam momentum range. So far the scans of p+p, p+Pb, Be+Be, and Ar+Sc interactions have been completed, samples of Pb+Pb data at three energies have already been taken and Xe+La collisions will be registered this year. Results from the different reactions are now emerging, in particular the energy dependence of hadron spectra and yields as well as fluctuations. This contribution presents status and preliminary results from this effort, as well as an outlook for future extensions of the strong interactions programme.

   nucl-exKnE Energ.Phys.(2018)·1 citation
7. 07*

   First measurement of helicity-dependent cross sections in pi0-eta photoproduction from quasi-free nucleons

   A. Käser🇨🇭 · M. Dieterle🇨🇭 · L. Witthauer🇨🇭 · S. Abt🇨🇭 · P. Achenbach🇩🇪 · P. Adlarson🇩🇪 · F. Afzal🇩🇪 · Z. Ahmed🇨🇦 · J. Ahrens🇩🇪 · J.R.M. Annand🇬🇧 · H.J. Arends🇩🇪 · M. Bashkanov🇬🇧 and 71 other authors

   The helicity-dependent cross sections for the photoproduction of ${\pi }^0\eta$ pairs have been measured for the first time. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with the combined Crystal Ball - TAPS calorimeter. The experiment used a polarized deuterated butanol target and a circularly polarized photon beam. This arrangement allowed the ${\sigma }_{1/2}$ (photon and target spin antiparallel) and ${\sigma }_{3/2}$ (parallel spins) components to be measured for quasi-free production of ${\pi }^0\eta$ pairs off protons and neutrons. The main finding is that the two helicity components contribute identically, within uncertainties, for both participant protons and neutrons. The absolute couplings for protons and neutrons are also identical. This means that nucleon resonances contributing to this reaction in the investigated energy range have almost equal electromagnetic helicity couplings, $A_{1/2}^{n,p}$ and $A_{3/2}^{n,p}$. Identical couplings for protons and neutrons are typical for $\Delta$ resonances and identical $A_{1/2}$ and $A_{3/2}$ components are only possible for $J\ge 3/2$ states, which constrains possible contributions of nucleon resonances.

   nucl-exPLB(2018)·11 citations
8. 08*

   Insight into Multiple Partonic Interactions and Production of Charmonia in p+p Collisions at the LHC energies

   Raghunath Sahoo🇮🇳 · Dhananjaya Thakur🇮🇳 · Sudipan De🇮🇳 · Soumya Dansana🇮🇳

   At the LHC energies, the underlying observables are of major topic of interest in high multiplicity $p+p$ collisions. Multiple Parton Interactions (MPI) is one of them, in which several interactions occur in a single $p+p$ collision. It is believed that MPI is the main reason behind the high multiplicity in $p+p$ collisions at the LHC. It was believed that MPI has only effect to the soft particle production, but recent ALICE result reveals that it can also affect the hard-particle production. In such case, the self normalized yield of heavy particle like $J/\psi$ shows an increasing trend with event multiplicity. In the present contribution, we discuss the energy and multiplicity dependence of charmonium production to understand the effects of MPI on charmonium production.

   ↳ hep-phhep-exnucl-exnucl-thSpringer Proc.Phys.(2019)·1 citation
9. 09*

   Coulomb exchange functional with generalized gradient approximation for self-consistent Skyrme Hartree-Fock calculations

   Tomoya Naito🇯🇵 · Xavier Roca-Maza🇮🇹 · Gianluca Colò🇮🇹 · Haozhao Liang🇯🇵

   We perform the self-consistent Skyrme Hartree-Fock calculation with the Coulomb exchange functional in the form of generalized gradient approximation (GGA). It is found that the Perdew-Burke-Ernzerhof GGA (PBE-GGA) Coulomb exchange functional is able to reproduce the exact-Fock energy for the nuclei in a large region of the nuclear chart with one adjustable parameter. The remaining error of Coulomb exchange energy by the GGA with respect to the exact-Fock energy dominantly comes from the functional-driven error.

   ↳ nucl-thcond-mat.othernucl-exPRC(2019)·10 citations
10. 10*

    Electromagnetic proton-neutron mass difference

    Oleksandr Tomalak🇩🇪

    We discuss the Cottingham formula and evaluate the proton-neutron electromagnetic mass difference exploiting the state-of-the-art phenomenological input. We decompose individual contributions to the mass splitting into Born, inelastic and subtraction terms. We evaluate the subtraction-function contribution from the experimental input only and the Born term accounting for the modern low-$Q^2$ data.

    ↳ hep-phnucl-exnucl-thEur.Phys.J.Plus(2020)·10 citations
11. 11*

    Chiral symmetry breaking generalizes in tensor theories

    P. Diaz🇰🇷 · J. A. Rosabal🇰🇷

    In this letter we uncover a new facet of chiral symmetry and the implications of its breaking in some theories. By generalizing the concept of chiral symmetry, tensor theories naturally arise. This novel approach adds to the known uses of tensor theories (quantum gravity, holography, entanglement,etc.) a possible link to QCD phenomena.

    ↳ hep-thhep-phnucl-ex2 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.