Tue·Apr 6, 2021Tuesday·April 6, 2021

1. 01*

   Determination of shear forces inside the proton

   V. D. Burkert🇺🇸 · L. Elouadrhiri🇺🇸 · F.X. Girod🇺🇸

   We report on the first determination of the shear forces quarks inside the proton from experimental data on deeply virtual Compton scattering. The maximum shear force of approximately 40 MeV/fm occurs near 0.6 fm from the proton center, indicating where confinement forces may be strongest. On the macroscopic scale of the earth surface, this force corresponds to the weight of a mass of about 650 kg. The shear forces in the proton reverse direction at r = 0.45 fm from the center.

   nucl-exhep-exhep-lathep-ph+164 citations
2. 02*

   Neutrino energy reconstruction from semi-inclusive samples

   R. González-Jiménez🇪🇸 · M. B. Barbaro🇮🇹 · J. A. Caballero🇪🇸 · T. W. Donnelly🇺🇸 · N. Jachowicz🇧🇪 · G. D. Megias🇪🇸 · K. Niewczas🇧🇪 · A. Nikolakopoulos🇧🇪 · J. W. Van Orden🇺🇸 · J. M. Udías🇪🇸

   We study neutrino-nucleus charged-current reactions on finite nuclei for the situation in which an outgoing muon and a proton are detected in coincidence, i.e., we focus on semi-inclusive cross sections. We limit our attention to one-body current interactions (quasielastic scattering) and assess the impact of different nuclear effects in the determination of the neutrino energy. We identify the regions in phase space where the neutrino energy can be reconstructed relatively well, and study whether the cross section in those regions is significant. Our results indicate that it is possible to filter more than 50% of all events according to the muon and proton kinematics, so that for the DUNE and T2K fluxes the neutrino energy can be determined with an uncertainty of less than 1% and 3%, respectively. Furthermore, we find that the reconstructed neutrino energy does not depend strongly on how one treats the final-state interactions and is not much affected by the description of the initial state. On the other hand, the estimations of the uncertainty on the neutrino energy show important sensitivity to the modeling of the initial state.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2022)·35 citations
3. 03*

   Coherent neutrino scattering and the Migdal effect on the quenching factor

   Jiajun Liao🇨🇳 · Hongkai Liu🇺🇸 · Danny Marfatia🇺🇸

   Recent measurements of the germanium quenching factor deviate significantly from the predictions of the standard Lindhard model for nuclear recoil energies below a keV. This departure may be explained by the Migdal effect in neutron scattering on germanium. We show that the Migdal effect on the quenching factor can mimic the signal of a light Z' or light scalar mediator in coherent elastic neutrino nucleus scattering experiments with reactor antineutrinos. It is imperative that the quenching factor of nuclei with low recoil energy thresholds be precisely measured close to threshold to avoid such confusion. This will also help in experimental searches of light dark matter.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2021)·25 citations
4. 04*

   Manipulating strong electromagnetic fields with the average transverse momentum of relativistic nuclear collisions

   Giuliano Giacalone🇩🇪 · Chun Shen🇺🇸

   We show that an event-shape engineering based on the mean transverse momentum of charged hadrons, $[p_t]$, provides an optimal handle on the strength of the magnetic field created in central heavy-ion collisions at high energy. This is established through quantitative evaluations of the correlation existing between the event-by-event magnetic field produced by the spectator protons in 5.02 TeV Pb+Pb collisions and the event-by-event $[p_t]$ at a given collision centrality. We argue that the event selection based on $[p_t]$ provides a better handle on the magnetic field than the more traditional selection based on the event ellipticities. Advantages brought by this new method for the experimental search of the chiral magnetic effect are discussed.

   ↳ nucl-thhep-exhep-phnucl-exEPJA(2021)·4 citations
5. 05*

   The "Folk Theorem" on Effective Field Theory: A Case for Nuclear Physics

   Mannque Rho🇫🇷

   Although largely unrecognized, Gerry Brown had played a seminal and prescient role for the development of the currently heralded "first-principles approach" to nuclear dynamics known as "nuclear effective field theory" ($n$EFT for short). I give a brief account in what way he entered -- together with his Korean colleagues -- at the earliest stage of its development and what he left behind for the future in paving the road to go {\it way beyond} the standard $n$EFT. I do this in the context of Gerry's original conceptual ideas conceived after the "dilepton fiasco" that indicate a surprising new role of hidden local and scale symmetries in nuclear physics.

   ↳ nucl-thnucl-ex1 citation
6. 06*

   Two-body wave functions and compositeness from scattering amplitudes: II. Application to the physical $N^{\ast }$ and ${\Delta }^{\ast }$ resonances

   Takayasu Sekihara🇯🇵

   The meson-baryon molecular components for the $N^{\ast }$ and ${\Delta }^{\ast }$ resonances are investigated in terms of the compositeness, which is defined as the norm of the two-body wave function from the meson-baryon scattering amplitudes. The scattering amplitudes are constructed in a $\pi N$-$\eta N$-$\sigma N$-$\rho N$-$\pi \Delta$ coupled-channels problem in a meson exchange model together with several bare $N^{\ast }$ and ${\Delta }^{\ast }$ states, and parameters are fitted so as to reproduce the on-shell $\pi N$ partial wave amplitudes up to the center-of-mass energy 1.9 GeV with the orbital angular momentum $L\le 2$. As a result, the Roper resonance $N(1440)$ is found to be dominated by the $\pi N$ and $\sigma N$ molecular components while the bare-state contribution is small. The squared wave functions in coordinate space imply that both in the $\pi N$ and $\sigma N$ channels the separation between the meson and baryon is about more than 1 fm for the $N(1440)$ resonance. On the other hand, dominant meson-baryon molecular components are not observed in any other $N^{\ast }$ and ${\Delta }^{\ast }$ resonances in the present model, although they have some fractions of the meson-baryon clouds.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2021)·10 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.