Thu·Jul 30, 2020Thursday·July 30, 2020

1. 01*

   Search for the $1/2^{+}$ intruder state in ${}^{35}$P

   M. Salathe (1)🇺🇸 · H. L. Crawford (1)🇺🇸 · A. O. Macchiavelli (1)🇺🇸 · B. P. Kay (2)🇺🇸 · C. R. Hoffman (2)🇺🇸 · A. D. Ayangeakaa (3 and 4)🇺🇸 · C. M. Campbell (1)🇺🇸 · R. M. Clark (1)🇺🇸 · M. Cromaz (1)🇺🇸 · P. Fallon (1)🇺🇸 · M. D. Jones (1)🇺🇸 · S. A. Kuvin (5) and 4 other authors

   The excitation energy of deformed intruder states (specifically the 2p2h bandhead) as a function of proton number $Z$ along $N=20$ is of interest both in terms of better understanding the evolution of nuclear structure between spherical ${}^{40}$Ca and the Island of Inversion nuclei, and for benchmarking theoretical descriptions in this region. At the center of the $N=20$ Island of Inversion, the npnh (where n=2,4,6) neutron excitations across a diminished $N=20$ gap result in deformed and collective ground states, as observed in ${}^{32}$Mg. In heavier isotones, npnh excitations do not dominate in the ground states, but are present in the relatively low-lying level schemes. With the aim of identifying the expected 2p2h$\otimes {\mathrm{s}}_{1/2^{+}}$ state in ${}^{35}$P, the only $N=20$ isotone for which the neutron 2p2h excitation bandhead has not yet been identified, the ${}^{36}$S(d,${}^3$He)${}^{35}$P reaction has been revisited in inverse kinematics with the HELical Orbit Spectrometer (HELIOS) at the Argonne Tandem Linac Accelerator System (ATLAS). While a candidate state has not been located, an upper limit for the transfer reaction cross-section to populate such a configuration within a 2.5 to 3.6\,MeV energy range, provides a stringent constraint on the wavefunction compositions in both ${}^{36}$S and ${}^{35}$P.

   nucl-exPRC(2020)·3 citations
2. 02*

   Comparison of recoil polarization in the ${}^{12}\mathrm{C}(\vec{e},e^{\prime }\vec{p})$ process for protons extracted from $s$ and $p$ shell

   T. Kolar🇸🇮 · S. Paul🇮🇱 · T. Brecelj🇸🇮 · P. Achenbach🇩🇪 · R. Böhm🇩🇪 · D. Bosnar🇭🇷 · E.O. Cohen🇮🇱 · M.O. Distler🇩🇪 · A. Esser🇩🇪 · C. Giusti🇮🇹 · M. Hoek🇩🇪 · D. Izraeli🇮🇱 and 20 other authors

   We present first measurements of the double ratio of the polarization transfer components $(P_x^{\prime }/P_z^{\prime }{)}_p/(P_x^{\prime }/P_z^{\prime }{)}_s$ for knock-out protons from $s$ and $p$ shells in ${}^{12}\mathrm{C}$ measured by the ${}^{12}\mathrm{C}(\vec{e},e^{\prime }\vec{p})$ reaction in quasi-elastic kinematics. The data are compared to theoretical predictions in relativistic distorted-wave impulse approximation. Our results show that differences between $s$- and $p$-shell protons, observed when compared at the same initial momentum (missing momentum) largely disappear when the comparison is done at the same proton virtuality. We observe no density-dependent medium modifications for protons from $s$ and $p$ shells with the same virtuality in spite of the large differences in the respective nuclear densities.

   nucl-exPLB(2020)·9 citations
3. 03*

   Heavy flavor and jet studies for the future Electron-Ion Collider

   Xuan Li🇺🇸

   The proposed high luminosity high energy Electron-Ion Collider (EIC) will explore the proton/nuclear structure in a wide Bjorken-x ($x_{BJ}$) and $Q^2$ phase space. Heavy flavor products are generated in initial collisions and have their hadronization influenced by the nuclear medium. Heavy flavor hadron and jet measurements at the future EIC will allow us to better constrain the nPDFs especially in the poorly constrained high $x_{BJ}$ region, precisely determine the quark/gluon fragmentation processes and directly study the quark/gluon energy loss within the nuclear medium. These measurements can constrain the cold nuclear medium effects for previous and ongoing heavy ion measurements at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). Silicon vertex/tracking detectors are essential to realize the heavy flavor and jet measurements at the EIC. Feasibility studies in simulation for proposed heavy flavor and jet observable with evaluated detector performance at the future EIC will be discussed.

   ↳ hep-exhep-phnucl-exPoS(2021)·7 citations
4. 04*

   QCD resummation on single hadron transverse momentum distribution with the thrust axis

   Zhong-Bo Kang🇺🇸 · Ding Yu Shao🇺🇸 · Fanyi Zhao🇺🇸

   We derive the transverse momentum dependent (TMD) factorization and resummation formula of the unpolarized transverse momentum distribution ($j_T$) for the single hadron production with the thrust axis in electron-positron collision. Two different kinematic regions are considered, including small transverse momentum limit $j_T\ll Q$, and joint transverse momentum and threshold limit $j_T\ll Q(1-z_h)\ll Q$, where $Q$ and $z_h$ are the hard scattering energy and the observed hadron momentum fraction. Using effective theory methods, we resum logarithms $\ln (Q/j_T)$ and $\ln (1-z_h)$ to all orders. In the end we present the differential cross sections and Gaussian widths calculated for the inclusive charged pion production and find that our results are consistent with the measurements reported by the Belle collaboration.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2020)·29 citations
5. 05*

   The Large Hadron-Electron Collider at the HL-LHC

   P. Agostini🇪🇸 · H. Aksakal🇹🇷 · S. Alekhin🇩🇪 · P. P. Allport🇬🇧 · N. Andari🇫🇷 · K. D. J. Andre🇬🇧 · D. Angal-Kalinin🇬🇧 · S. Antusch🇨🇭 · L. Aperio Bella🇨🇳 · L. Apolinario🇵🇹 · R. Apsimon🇬🇧 · A. Apyan🇦🇲 and 325 other authors

   The Large Hadron electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High Luminosity--Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron-proton and proton-proton operation. This report represents an update of the Conceptual Design Report (CDR) of the LHeC, published in 2012. It comprises new results on parton structure of the proton and heavier nuclei, QCD dynamics, electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics in extending the accessible kinematic range in lepton-nucleus scattering by several orders of magnitude. Due to enhanced luminosity, large energy and the cleanliness of the hadronic final states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, the report represents a detailed updated design of the energy recovery electron linac (ERL) including new lattice, magnet, superconducting radio frequency technology and further components. Challenges of energy recovery are described and the lower energy, high current, 3-turn ERL facility, PERLE at Orsay, is presented which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution and calibration goals which arise from the Higgs and parton density function physics programmes. The paper also presents novel results on the Future Circular Collider in electron-hadron mode, FCC-eh, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies.

   ↳ hep-exhep-phnucl-exnucl-thJ.Phys.G(2021)·442 citations
6. 06*

   Neutrinoless Double-Electron Capture

   K. Blaum🇩🇪 · S. Eliseev🇩🇪 · F. A. Danevich🇺🇦 · V. I. Tretyak🇺🇦 · Sergey Kovalenko🇨🇱 · M. I. Krivoruchenko🇷🇺 · Yu. N. Novikov🇷🇺 · J. Suhonen🇫🇮

   Double-beta processes play a key role in the exploration of neutrino and weak interaction properties, and in the searches for effects beyond the Standard Model. During the last half century many attempts were undertaken to search for double-beta decay with emission of two electrons, especially for its neutrinoless mode ($0\nu 2{\beta }^{-}$), the latter being still not observed. Double-electron capture (2EC) was not in focus so far because of its in general lower transition probability. However, the rate of neutrinoless double-electron capture ($0\nu 2$EC) can experience a resonance enhancement by many orders of magnitude in case the initial and final states are energetically degenerate. In the resonant case, the sensitivity of the $0\nu 2$EC process can approach the sensitivity of the $0\nu 2{\beta }^{-}$ decay in the search for the Majorana mass of neutrinos, right-handed currents, and other new physics. We present an overview of the main experimental and theoretical results obtained during the last decade in this field. The experimental part outlines search results of 2EC processes and measurements of the decay energies for possible resonant $0\nu$2EC transitions. An unprecedented precision in the determination of decay energies with Penning traps has allowed one to refine the values of the degeneracy parameter for all previously known near-resonant decays and has reduced the rather large uncertainties in the estimate of the $0\nu 2$EC half-lives. The theoretical part contains an updated analysis of the electron shell effects and an overview of the nuclear structure models, in which the nuclear matrix elements of the $0\nu 2$EC decays are calculated. One can conclude that the decay probability of $0\nu$2EC can experience a significant enhancement in several nuclides.

   ↳ hep-phnucl-exnucl-thphysics.atom-phRMP(2020)·68 citations
7. 07*

   MeV-scale performance of water-based and pure liquid scintillator detectors

   B. J. Land🇺🇸 · Z. Bagdasarian🇺🇸 · J. Caravaca🇺🇸 · M. Smiley🇺🇸 · M. Yeh🇺🇸 · G. D. Orebi Gann🇺🇸

   This paper presents studies of the performance of water-based liquid scintillator in both 1-kt and 50-kt detectors. Performance is evaluated in comparison to both pure water Cherenkov detectors and a nominal model for pure scintillator detectors. Performance metrics include energy, vertex, and angular resolution, along with a metric for ability to separate the Cherenkov from the scintillation signal, as being representative of various particle identification capabilities that depend on the Cherenkov / scintillation ratio. We also modify the time profile of scintillation light to study the same performance metrics as a function of rise and decay time. We go on to interpret these results in terms of their impact on certain physics goals, such as solar neutrinos and the search for Majorana neutrinos. This work supports and validates previous results, and the assumptions made therein, by using a more complete detector model and full reconstruction. We confirm that a high-coverage, 50-kt detector would be capable of better than 10 (1)\% precision on the CNO neutrino flux with a WbLS (pure LS) target in 5 years of data taking. A 1-kt LS detector, with a conservative 50\% fiducial volume of 500~t, can achieve a better than 5\% detection. Using the liquid scintillator model, we find a sensitivity into the normal hierarchy region for Majorana neutrinos, with half life sensitivity of $T_{1/2}^{0\nu \beta \beta }>1.4\times 10^{28}$ years at 90\% CL for 10 years of data taking with a Te-loaded target.

   ↳ physics.ins-dethep-exnucl-exPRD(2021)·48 citations
8. 08*

   Search for event bursts in XMASS-I associated with gravitational-wave events

   XMASS Collaboration: K. Abe🇯🇵 · K. Hiraide🇯🇵 · K. Ichimura🇯🇵 · Y. Kishimoto🇯🇵 · K. Kobayashi🇯🇵 · M. Kobayashi🇯🇵 · S. Moriyama🇯🇵 · M. Nakahata🇯🇵 · H. Ogawa🇯🇵 · K. Sato🇯🇵 · H. Sekiya🇯🇵 · T. Suzuki🇯🇵 and 24 other authors

   We performed a search for event bursts in the XMASS-I detector associated with 11 gravitational-wave events detected during LIGO/Virgo's O1 and O2 periods. Simple and loose cuts were applied to the data collected in the full 832 kg xenon volume around the detection time of each gravitational-wave event. The data were divided into four energy regions ranging from keV to MeV. Without assuming any particular burst models, we looked for event bursts in sliding windows with various time width from 0.02 to 10 s. The search was conducted in a time window between $-$400 and $+$10,000 s from each gravitational-wave event. For the binary neutron star merger GW170817, no significant event burst was observed in the XMASS-I detector and we set 90% confidence level upper limits on neutrino fluence for the sum of all the neutrino flavors via coherent elastic neutrino-nucleus scattering. The obtained upper limit was (1.3-2.1)$\times 10^{11}$ cm${}^{-2}$ under the assumption of a Fermi-Dirac spectrum with average neutrino energy of 20 MeV. The neutrino fluence limits for mono-energetic neutrinos in the energy range between 14 and 100 MeV were also calculated. Among the other 10 gravitational wave events detected as the binary black hole mergers, a burst candidate with a 3.0$\sigma$ significance was found at 1801.95-1803.95 s in the analysis for GW151012. However, no significant deviation from the background in the reconstructed energy and position distributions was found. Considering the additional look-elsewhere effect of analyzing the 11 GW events, the significance of finding such a burst candidate associated with any of them is 2.1$\sigma$.

   ↳ astro-ph.HEastro-ph.IMhep-exnucl-ex+1Astropart.Phys.(2021)·7 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.