Fri·Nov 11, 2022Friday·November 11, 2022

1. 01*

   Exploring sQGP and Small Systems

   Debasish Das🇮🇳

   A strongly interacting Quark-Gluon Plasma (sQGP) is created in the high energy heavy ion collisions at RHIC and LHC. Our present understanding of sQGP as a very good liquid with astonishingly low viscosity is reviewed. With the arrival of the interesting results from LHC in high-energy p+p and p+A, a new endeavour to characterize the transition from these small systems to heavy ions (A+A) is now in place, since, even the small systems showed prominent similarities to heavy ions in the rising multiplicity domains. An outlook of future possibilities for better measurements is also made at the end of this brief review.

   nucl-exhep-exhep-phhep-th+1Int.J.Mod.Phys.A(2021)·4 citations
2. 02*

   System-size dependence of particle production at mid- and forward rapidity with ALICE

   Abhi Modak (for the ALICE Collaboration)🇮🇳

   The pseudorapidity densities of charged particles and inclusive photons produced in high energy nuclear collisions are essential observables to characterise the global properties of the collisions, such as the achieved energy density, and to provide important constraints for Monte Carlo model calculations. In the LHC Run 1 and Run 2 configurations, ALICE had large coverage to measure charged particles over a pseudorapidity range ($-3.4<\eta <5.0$), combining the data from the Silicon Pixel Detector (SPD) and the Forward Multiplicity Detector (FMD). The inclusive photons are measured at forward rapidity using the Photon Multiplicity Detector (PMD), covering the pseudorapidity range $2.3<\eta <3.9$. New results on charged-particle pseudorapidity densities measured in pp, p$-$Pb, and Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV using Run 1 and Run 2 data are presented. Inclusive photon production is reported for p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV. The charged-particle rapidity densities are derived from the measured charged-particle pseudorapidity densities, and then parameterized by a normal distribution. This allows us to study the evolution of the width of the rapidity distributions as a function of the number of participants in all three collision systems. The performance of the new Inner Tracking System (ITS) designed for ALICE Run 3 configuration is also discussed for pilot beam pp collisions at $\sqrt{s}$ = 0.9 TeV.

   nucl-exhep-exPoS·1 citation
3. 03*

   Mueller's dipole wave function in QCD: emergent KNO scaling in the double logarithm limit

   Yizhuang Liu🇵🇱 · Maciej A. Nowak🇵🇱 · Ismail Zahed🇺🇸

   We analyze Mueller's QCD dipole wave function evolution in the double logarithm approximation (DLA). Using complex analytical methods, we show that the distribution of dipole in the wave function (gluon multiplicity distribution) asymptotically satisfies the Koba-Nielsen-Olesen (KNO) scaling, with a non-trivial scaling function $f(z)$ with $z=\frac{n}{\bar{n}}$. The scaling function decays exponentially as $2(2.55{)}^{2}z{e}^{-\frac{z}{0.3917}}$ at large $z$, while its growth is log-normal as $e^{-\frac{1}{2}{\ln }^{2}z}$ for small-$z$. A detailed analysis of the Fourier-Laplace transform of $f(z)$, allows for performing the inverse Fourier transform, and access the non-asymptotic bulk-region around the peak. The bulk and asymptotic results are shown to be in good agreement with the measured hadronic multiplicities in DIS, as reported by the H1 collaboration at HERA in the region of large $Q^2$. A numerical tabulation of $f(z)$ is included. Remarkably, the same scaling function is found to emerge in the resummation of double logarithms in the evolution of jets. Using the generating function approach, we show why this is the case. The absence of KNO scaling in non-critical and super-renormalizable theories is briefly discussed. We also discuss the universal character of the entanglement entropy in the KNO scaling limit, and its measurement using the emitted multiplicities in DIS and $e^{+}{e}^{-}$ annihilation.

   ↳ hep-phhep-thnucl-exnucl-thPRD(2023)·24 citations
4. 04*

   New methods to achieve meson, muon and gamma light sources through asymmetric electron positron collisions

   Dawei Fu🇨🇳 · Alim Ruzi🇨🇳 · Meng Lu🇨🇳 · Qiang Li🇨🇳

   We propose methods to produce energetic meson beams such as charged and neutral Kaons, which are boosted to be collimated and with relatively long life time. The first type of methods is based on asymmetric electron positron collisions with a center of mass energy of, e.g., 1020 MeV, and Kaons can be produced at a rate of $10^{4-5}/s$. The electron and positron beams are either asymmetric in energy, e.g., 10 GeV electron beam with 26 MeV positron beam, or asymmetric in space, e.g., 10 GeV electron and positron beams collisions separated with a angle around 0.05 radius. Such proposals should be able to be achieved with a reasonable budget. The other type of method is relying on TeV positron on target experiment, where Kaon beams can be achieved at around $10^7$ per bunch crossing. Such Kaon beams are clean with small contamination, and can have great physics potential on, e.g., hyperon searches through Kaon nuclei collision, Kaon rare decay measurement, and Kaon proton or Kaon lepton collisions. The same technique with very asymmetric electron positron collisions can also be extended to other final states such as pions and tau leptons.

   ↳ hep-phhep-exnucl-exphysics.acc-phInt.J.Mod.Phys.A(2023)·2 citations
5. 05*

   Skin values of ${}^{208}$Pb and ${}^{48}$Ca determined from reaction cross sections (published in Results in Physics)

   Tomotsugu Wakasa🇯🇵 · Shingo Tagami🇯🇵 · Masanobu Yahiro🇯🇵

   The PREX and the CREX group reported their skin values. Using the Love-Franey (LF) $t$-matrix folding model with the neutron and proton densities scaled to the neutron radius $r_{\mathrm{n}}^{208}(PREX2)$ and the proton radius of the electron scattering, we found that the model reproduces ${\sigma }_R$ for p+ ${}^{208}$Pb scattering at $E_{\mathrm{lab}}=534.1,549,806$MeV. Zenihiro {\it el al. } deduce neutron radii $r_{\mathrm{n}}^{48,40}(\exp )$ from proton elastic scattering, whereas we determine $r_{\mathrm{m}}^{40}(\exp )=3.361\pm 0.075$fm from measured ${\sigma }_R$ for ${}^4$He+ ${}^{40}$Ca scattering. Our first aim is to determine $r_{\mathrm{skin}}^{208}$ from measured ${\sigma }_R$ of p+${}^{208}$Pb scattering at $E_{\mathrm{lab}}=534.1,549,806$MeV by using the LF $t$-matrix folding model. Our second aim is to determine $r_{\mathrm{skin}}^{48}$ from the $r_{\mathrm{m}}^{40}(\exp )$ and $\Delta \equiv r_{\mathrm{m}}^{48}(\exp )-r_{\mathrm{m}}^{40}(\exp )$ that is evaluated from the $r_{\mathrm{n}}^{48,40}(\exp )$ and the $r_{\mathrm{p}}^{48,40}(\exp )$ calculated with the isotope shift method based on the electron scattering. For the first aim, we use the LF $t$-matrix model with the densities scaled from the D1S-GHFB+AMP neutron density. The D1M-GHFB+AMP is used to estimate a theoretical error. The resulting skin values are $r_{\mathrm{skin}}^{208}=0.324\pm 0.047$fm for D1S and $r_{\mathrm{skin}}^{208}(\exp )=0.333\pm 0.047$fm for D1M. The $\Delta =0.109$fm and $r_{\mathrm{m}}^{40}(\exp )=3.361\pm 0.075$fm yield $r_{\mathrm{m}}^{48}=3.470\pm 0.075$fm, leading to $r_{\mathrm{skin}}^{48}=0.144\pm 0.075$fm. We conclude that $r_{\mathrm{skin}}^{208}(\exp )=0.324\pm (0.047{)}_{\exp }\pm (0.009{)}_{\mathrm{th}}\mathrm{fm}$ for p scattering at $E_{\mathrm{lab}}=534.1,549,806$MeV. Our skin values are consistent with the PREX2 and CREX values.

   ↳ nucl-thnucl-ex0 citations
6. 06*

   The proton radius and its relatives -- much ado about nothing?

   Ulf-G. Meißner🇩🇪

   I summarize the dispersion-theoretical analysis of the nucleon electromagnetic form factors. Special emphasis is given on the extraction of the proton charge radius and its relatives, the proton magnetic radius as well as the neutron magnetic radius. Some recent work on the hyperfine splitting in leptonic hydrogen and on radiative corrections to muon-proton scattering is also discussed. Some views on future studies are given.

   ↳ hep-phhep-exhep-latnucl-ex+1J.Phys.Conf.Ser.(2023)·9 citations
7. 07*

   Growth and characterization of thorium-doped calcium fluoride single crystals

   Kjeld Beeks🇦🇹 · Tomas Sikorsky · Veronika Rosecker · Martin Pressler · Fabian Schaden🇦🇹 · David Werban · Niyusha Hosseini🇦🇹 · Lukas Rudischer · Felix Schneider · Patrick Berwian · Jochen Friedrich · Dieter Hainz and 4 other authors

   We have grown ${}^{232}$Th:CaF${}_2$ and ${}^{229}$Th:CaF${}_2$ single crystals for investigations on the VUV laser-accessible first nuclear excited state of ${}^{229}$Th. To reach high doping concentrations despite the extreme scarcity (and radioactivity) of ${}^{229}$Th, we have scaled down the crystal volume by a factor 100 compared to established commercial or scientific growth processes. We use the vertical gradient freeze method on 3.2 mm diameter seed single crystals with a 2 mm drilled pocket, filled with a co-precipitated CaF${}_2$:ThF${}_4$:PbF${}_2$ powder in order to grow single crystals. Concentrations of $4\cdot 10^{19}$ cm${}^{-3}$ have been realized with ${}^{232}$Th with good ($>$10%) VUV transmission. However, the intrinsic radioactivity of ${}^{229}$Th drives radio-induced dissociation during growth and radiation damage after solidification. Both lead to a degradation of VUV transmission, limiting the ${}^{229}$Th concentration to $<5\cdot 10^{17}$ cm${}^{-3}$.

   ↳ cond-mat.mtrl-scinucl-exphysics.atom-phSci.Rep.(2023)·30 citations
8. 08*

   Phenomenological description of the ${\pi }^{-}{\pi }^{+}$ $S$-waves in $D^{+}\to {\pi }^{-}{\pi }^{+}{\pi }^{+}$ and $D_s^{+}\to {\pi }^{-}{\pi }^{+}{\pi }^{+}$ decays: The problem of phases

   N.N. Achasov🇷🇺 · G.N. Shestakov🇷🇺

   We present a phenomenological description of the LHCb data for the magnitudes and phases of the ${\pi }^{-}{\pi }^{+}$ $S$-wave amplitudes in the $D^{+}\to {\pi }^{-}{\pi }^{+}{\pi }^{+}$ and $D_s^{+}\to {\pi }^{-}{\pi }^{+}{\pi }^{+}$ decays. We operate within a simple model that takes into account the known pair interactions of particles in coupled channels. The seed complex amplitudes for various intermediate state production are assumed to be independent of the energy. Their values are determined by fitting. This model gives the satisfactorily description of virtually all features of the energy dependence of the experimentally measured $S$-wave amplitudes in the $D^{+}\to {\pi }^{-}{\pi }^{+}{\pi }^{+}$ and $D_s^{+}\to {\pi }^{-}{\pi }^{+}{\pi }^{+}$ decays in the regions $2m_{\pi }<m_{{\pi }^{-}{\pi }^{+}}<1.39\text{mbox}GeV$ and $2m_{\pi }<m_{{\pi }^{-}{\pi }^{+}}<1.29\text{mbox}GeV$, respectively.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2023)·3 citations
9. 09*

   Variable Energy X-ray Fluorescence Source

   S. R. Elliott🇺🇸 · E. M. Bond🇺🇸 · B. Dodson🇺🇸 · G. Rusev🇺🇸 · R. Massarczyk🇺🇸 · S. J. Meijer🇺🇸 · M. Stortini🇺🇸 · C. Wiseman🇺🇸

   We detail the design of a variable energy, x-ray fluorescence source using a low activity (1.8$\times 10^6$~dpm) \nuc{99}{Tc} $\beta$ source that irradiates thin foils. By rotating the source among foils of Ti, Zn, Nb, Ag, and Au, the device produces x rays between 4 and 70 keV at a rate near 1 Hz. When the source is placed in a storage position, the external radiation is non-detectable. The design of the shielding and rotation mechanism permits use in vacuum and at liquid nitrogen temperature. The design is intended for the study of the low energy response to radiation impinging upon Ge detector surfaces. The source will be useful for understanding the detector response in large-scale Ge arrays such as \textsc{Majorana} and LEGEND.

   ↳ physics.ins-detnucl-exJINST(2023)·0 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.