Tue·Oct 3, 2023Tuesday·October 3, 2023

1. 01*

   Neutrons from projectile fragmentation at 600 MeV/nucleon

   P. Pawłowski🇵🇱 · J. Brzychczyk🇵🇱 · N. Buyukcizmeci🇹🇷 · H. T. Johansson🇸🇪 · W. Trautmann🇩🇪 · A. Wieloch🇵🇱 · P. Adrich🇵🇱 · T. Aumann🇩🇪 · T. Barczyk🇵🇱 · S. Bianchin🇩🇪 · K. Boretzky🇩🇪 · A. S. Botvina🇩🇪 and 24 other authors

   The neutron emission in projectile fragmentation at relativistic energies was studied with the Large-Area-Neutron-Detector LAND coupled to the ALADIN forward spectrometer at the GSI Schwerionen-Synchrotron (SIS). Stable 124Sn and radioactive 107Sn and 124La beams with an incident energy of 600 MeV/nucleon were used to explore the N/Z dependence of the identified neutron source. A cluster-recognition algorithm is applied for identifying individual particles within the hit distributions registered with LAND. The obtained momentum distributions are extrapolated over the full phase space occupied by the neutrons from the projectile-spectator source. The mean multiplicities of spectator neutrons reach values of up to about 11 and depend strongly on the isotopic composition of the projectile. An effective source temperature of T \approx 2-5 MeV, monotonically increasing with decreasing impact parameter, is deduced from the transverse momentum distributions. For the interpretation of the data, calculations with the statistical multifragmentation model were performed. The variety of excited projectile spectators assumed to decay statistically is represented by an ensemble of excited sources with parameters determined previously from the fragment production observed in the same experiments. The obtained agreement is very satisfactory for more peripheral collisions where, according to the model, neutrons are mainly emitted during the secondary decays of excited fragments. The neutron multiplicity in more central collisions is underestimated, indicating that other sources besides the modeled statistical breakup contribute to the observed neutron yield. The choice made for the symmetry-term coefficient of the liquid-drop description of produced fragments has a weak effect on the predicted neutron multiplicities.

   nucl-exPRC(2023)·6 citations
2. 02*

   First measurement of $\Lambda N$ inelastic scattering with $\Lambda$ from $e^{+}{e}^{-}\to J/\psi \to \Lambda \bar{\Lambda }$

   BESIII Collaboration: M. Ablikim · M. N. Achasov · P. Adlarson · O. Afedulidis · X. C. Ai · R. Aliberti · A. Amoroso · Q. An · Y. Bai · O. Bakina · I. Balossino · Y. Ban and 638 other authors

   Using an $e^{+}{e}^{-}$ collision data sample of $(10087\pm 44)\times 10^{6}J/\psi$ events taken at the center-of-mass energy of $3.097\mathrm{GeV}$ by the BESIII detector at the BEPCII collider, the process $\Lambda +N\to {\Sigma }^{+}+X$ is studied for the first time employing a novel method. The ${\Sigma }^{+}$ hyperons are produced by the collisions of $\Lambda$ hyperons from $J/\psi$ decays with nuclei in the material of the BESIII detector. The total cross section of $\Lambda {+}^9\mathrm{Be}\to {\Sigma }^{+}+X$ is measured to be $\sigma =(37.3\pm 4.7\pm 3.5)\mathrm{mb}$ at $\Lambda$ beam momenta within $[1.057,1.091]\mathrm{GeV}/c$, where the uncertainties are statistical and systematic, respectively. This analysis is the first study of $\Lambda$-nucleon interactions at an $e^{+}{e}^{-}$ collider, providing information and constraints relevant for the strong-interaction potential, the origin of color confinement, the unified model for baryon-baryon interactions, and the internal structure of neutron stars.

   nucl-exhep-exPRC(2024)·23 citations
3. 03*

   Scintillation characteristics of the EJ-299-02H scintillator

   N. Floyd🇺🇸 · Md. T. Hassan🇺🇸 · Z. Tang🇨🇳 · M. Krivos · M. Blatnik🇺🇸 · S. M. Clayton🇺🇸 · C. Cude-Woods · A. T. Holley🇺🇸 · T. M. Ito🇺🇸 · B. A. Johnson🇺🇸 · C.-Y. Liu · M. Makela and 6 other authors

   A study of the dead layer thickness and quenching factor of a plastic scintillator for use in ultracold neutron (UCN) experiments is described. Alpha spectroscopy was used to determine the thickness of a thin surface dead layer, and the relative light outputs from the decay of ${}^{241}$Am and Compton scattering of electrons were used to extract the quenching parameter. With these characteristics of the material known, the light yield of the scintillator can be calculated. The ability to make these scintillators deuterated, accompanied by its relatively thin dead layer, make it ideal for use in UCN experiment, where the light yield of decay electrons and alphas from neutron capture are critical for counting events.

   ↳ physics.ins-detnucl-exRev.Sci.Instrum.(2024)·4 citations
4. 04*

   Determination of the moments of the proton charge density: is there a proton radius puzzle?

   M. Atoui · M.B. Barbaro · M. Hoballah · C. Keyrouz · R. Kunne · M. Lassaut · D. Marchand · G. Quemener · E. Voutier

   The charge radius of the proton can be determined using two different kinds of experiments: the spectroscopy technique, measuring the hyperfine structure of hydrogen atoms, and the scattering technique, deducing the radius from elastic lepton scattering off a proton target. These two methods lead to quite different results, a discrepancy known as the "proton radius puzzle ". To shed light on this problem, we have proposed a novel method for the determination of spatial moments from densities expressed in the momentum space. This method provides a direct access not only to the second order moment, directly related to the proton radius, but to all moments of any real order larger than -3. The method is applied to the global analysis of proton electric form factor experimental data from Rosenbluth separation and low-$Q^2$ experiments, paying specific attention to the evaluation of the systematic errors. Within this analysis, the integer order moments of the proton charge density are evaluated, the moment of second order leading to a new determination of the proton charge radius.

   ↳ nucl-thhep-phnucl-exNucl.Theor.(2023)·1 citation
5. 05*

   Neutron-induced fission reaction studies with minor actinides using a double Frisch grid fission detector

   Chandrabhan Yadav · Dvir Ben Simhon · Moshe Friedman🇺🇸

   Neutron-induced fission cross-section studies are being pursued with a double Frisch grid fission detector. We are working towards conducting neutron-induced fission cross-section measurements of high priority 241Am(n, f) and 244,245Cm(n, f) fission reactions in the energy range of 1-2000 keV. These measurements of high priority (n, f) reactions cross-sections from the OECD Nuclear Energy Agency High Priority Request List (HPRL), are identified as reactions that require improved data in the energy range of 1-2000 keV for the safe and economic design of next-generation fast nuclear reactors. The 7Li(p, n) reaction at various proton energies from 1.9 MeV to 3.6 MeV will be used to produce neutron flux to conduct neutron-induced fission cross-section studies. In the present special issue contribution paper, we are presenting the characterization study of the double Frisch grid fission detector. The detector is characterized with a 252Cf (spontaneous fission) source. The chamber consists of two cylindrical ionization sections in a back-to-back geometry sharing a common cathode. Each section consists of a cathode, guard rings, a grid, and an anode. The grids are made as a wire plane. The separation between the cathode and grid is 5.3 cm, and the grid to the anode is 1.2 cm. The source is mounted on a common cathode, and the chamber is operated at approximately 800 Torr pressure of P-10 gas mixture. The data acquisition with the digital data acquisition module CAEN N6725 is being set up and the preliminary analysis of the chamber performance suggests that the detector operation is good and stable. Further work with regard to employing trigger from the cathode and incorporating energy loss corrections are being pursued.

   ↳ physics.ins-detnucl-ex0 citations
6. 06*

   Shell-model study of ${\beta }^{+}$/EC-decay half-lives for $Z=21-30$ nuclei

   Vikas Kumar · Praveen C. Srivastava🇮🇳

   In the present work, we have reported ${\beta }^{+}$/EC-decay half-lives for $Z=21-30$ nuclei using large-scale shell-model. %and N $\le$ A recent study shows that some proton-rich nuclei in this region belong to the island of inversion. We have performed calculations for these nuclei using KB3G effective interaction, while for Ni, Cu, and Zn nuclei we have used JUN45 effective interaction in the $f_{5/2}p{g}_{9/2}$ model space. The calculated quenching factors for $fp$ and $f_{5/2}p{g}_{9/2}$ space using KB3G and JUN45 effective interactions are also reported. Shell-model results of $\beta$-decay half-lives, excitation energies, log$ft$ values, and branching fractions are discussed and compared with the available experimental data. We have obtained a reasonable agreement with the available data.

   ↳ nucl-thnucl-exEPJA(2023)·5 citations
7. 07*

   Nucleon electric polarizabilities and nucleon-pion scattering at physical pion mass

   Xuan-He Wang🇨🇳 · Zhao-Long Zhang🇨🇳 · Xiong-Hui Cao🇨🇳 · Cong-Ling Fan🇨🇳 · Xu Feng🇨🇳 · Yu-Sheng Gao🇨🇳 · Lu-Chang Jin🇺🇸 · Chuan Liu🇨🇳

   We present a lattice QCD calculation of the nucleon electric polarizabilities at the physical pion mass. Our findings reveal the substantial contributions of the $N\pi$ states to these polarizabilities. Without considering these contributions, the lattice results fall significantly below the experimental values, consistent with previous lattice studies. This observation has motivated us to compute both the parity-negative $N\pi$ scattering up to a nucleon momentum of $\sim 0.5$ GeV in the center-of-mass frame and corresponding $N{\gamma }^{\ast }\to N\pi$ matrix elements using lattice QCD. Our results confirm that incorporating dynamic $N\pi$ contributions is crucial for a reliable determination of the polarizabilities from lattice QCD. This methodology lays the groundwork for future lattice QCD investigations into various other polarizabilities.

   ↳ hep-lathep-exhep-phnucl-exPRL(2024)·22 citations
8. 08*

   Numerical Simulations of Charge Trapping in Germanium Strip Detectors

   Steven E. Boggs · Sean N. Pike

   Charge trapping in germanium detectors will inevitably impact their excellent spectral performance. Disordered regions in the germanium crystal structure, either created in the material during processing or induced by radiation exposure, will affect the Charge Collection Efficiency (CCE), degrading the spectral resolution. Here we present numerical simulations of charge trapping effects on the anode and cathode signals for cross-strip germanium detectors. We discuss the assumptions behind our model of trapping, which accounts for both the drift length and thermal motion of the charge carriers. We present simulated CCE curves as a function of interaction depth within the detectors, and develop a technique for benchmarking these simulations against measured data. Comparison with measured CCE curves are presented. We are developing these numerical models with a goal of characterizing, and ultimately correcting, the effects of radiation damage on the spectral resolution of germanium cross-strip detectors.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·6 citations
9. 09*

   Particle physics in the sub-keV energy regime

   Charles Mark Lewis🇺🇸

   Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) and other rare-event physics searches, like dark matter detection, have been especially furthered by increasing sensitivity to low-energy particle interactions. Experiments using multiple detector technologies have sought CE$\nu$NS at the most intense terrestrial sources of neutrinos: spallation facilities and nuclear reactors. This thesis reports on the feasibility of using cryogenic pure CsI as an improved next-generation CE$\nu$NS target at the up-and-coming European Spallation Source. Calibrations and simulations presented here predict an increase by a factor of at least $\sim 33$ in the rate of observable neutrino-induced events per unit mass, compared to past use of room-temperature CsI[Na]. Also reported is the first measurement of CE$\nu$NS from antineutrinos at the Dresden Generating Station, a power nuclear reactor, employing a large-mass semiconducting germanium diode dubbed NCC-1701. In each section on detecting these neutrino couplings, the importance of understanding device response to low-energy nuclear recoils is highlighted. Finally, finding synergy for tools developed to extricate sub-keV CE$\nu$NS signals, a search for the exotic mode of muon decay ${\mu }^{+}\to e^{+}X$ was performed. New sensitivity limits in previously untouched parameter space for a massive boson dark matter candidate of cosmological interest are presented.

   ↳ physics.ins-detastro-ph.COhep-exnucl-ex5 citations
10. 10*

    Broadening of particle distributions in electron- and (anti)neutrino-nucleus scattering from QED interactions

    Oleksandr Tomalak🇺🇸 · Ivan Vitev🇺🇸

    Proper interpretation of past, current, and future data on lepton-nucleus reactions requires a clear separation between quantum electrodynamics (QED) and strong interaction effects inside the nucleus. First studies of QED in-medium lepton dynamics have set a theoretical framework to derive electron-nucleus and (anti)neutrino-nucleus cross-section corrections. We employ this approach to quantitatively compute the effects of Glauber photon-mediated multiple re-scattering within the nuclear medium. We find that the relativistic charged lepton acquires momentum of order $10\mathrm{MeV}$ transverse to its direction of propagation inside the nucleus. This broadening sizably deflects expected electron tracks and suppresses scattering cross sections. Precise extraction of the nucleon and nuclear structure by electron and muon probes should, thus, take the QED nuclear medium angular redistribution of particles into account. Our results further show that the associated effects in (anti)neutrino-nucleus scattering with measured final-lepton energy are significant only at the kinematical endpoints.

    ↳ hep-phhep-exnucl-exnucl-thPRD(2023)·6 citations
11. 11*

    Flavor Fragmentation Function Factorization

    Andrew J. Larkoski🇺🇸 · Duff Neill🇺🇸

    A definition of partonic jet flavor that is both theoretically well-defined and experimentally robust would have profound implications for measurements and predictions especially for heavy flavor applications. Recently, a definition of jet flavor was introduced as the net flavor flowing along the direction of the Winner-Take-All axis of a jet which is soft safe to all orders, but not collinear safe. Here, we exploit the lack of collinear safety and propose a factorization theorem of perturbative flavor fragmentation functions that resum collinear divergences and describe the evolution of flavor from the short distance of jet production to the long distance at which hadronization occurs. Collinear flavor evolution is governed by a small modification of the DGLAP equations. We present a detailed all-orders analysis and identify exact relations that must hold amongst the various anomalous dimensions by probability conservation and the existence of fixed points of the renormalization group flow. We explicitly validate the factorization theorem at one-loop order, and demonstrate its consistency at two loops in particular flavor channels. Starting at two-loops, constraints on phase space imposed by flavor measurements potentially allow for non-trivial soft contributions, but we demonstrate that they are scaleless and so explicitly vanish, ensuring that soft particles are summed inclusively and all divergences are exclusively collinear in nature. This factorization theorem opens the door to precision calculations with identified flavor in the infrared.

    ↳ hep-phhep-exnucl-exnucl-thJHEP(2024)·4 citations
12. 12*

    The Optimal use of Segmentation for Sampling Calorimeters

    Fernando Torales Acosta🇺🇸 · Bishnu Karki🇺🇸 · Piyush Karande🇺🇸 · Aaron Angerami🇺🇸 · Miguel Arratia🇺🇸 · Kenneth Barish🇺🇸 · Ryan Milton🇺🇸 · Sebastián Morán🇺🇸 · Benjamin Nachman🇺🇸 · Anshuman Sinha🇺🇸

    One of the key design choices of any sampling calorimeter is how fine to make the longitudinal and transverse segmentation. To inform this choice, we study the impact of calorimeter segmentation on energy reconstruction. To ensure that the trends are due entirely to hardware and not to a sub-optimal use of segmentation, we deploy deep neural networks to perform the reconstruction. These networks make use of all available information by representing the calorimeter as a point cloud. To demonstrate our approach, we simulate a detector similar to the forward calorimeter system intended for use in the ePIC detector, which will operate at the upcoming Electron Ion Collider. We find that for the energy estimation of isolated charged pion showers, relatively fine longitudinal segmentation is key to achieving an energy resolution that is better than 10% across the full phase space. These results provide a valuable benchmark for ongoing EIC detector optimizations and may also inform future studies involving high-granularity calorimeters in other experiments at various facilities.

    ↳ physics.ins-detcs.LGhep-exhep-ph+1JINST(2024)·8 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.