Mon·Mar 23, 2020Monday·March 23, 2020

1. 01*

   Neutron-hole strength in N = 81 nuclei

   A. M. Howard · S. J. Freeman🇬🇧 · D. K. Sharp🇬🇧 · T. Bloxham · J. A. Clark · C. M. Deibel🇺🇸 · B. P. Kay🇺🇸 · P. D. Parker · J. P. Schiffer🇺🇸 · J. S. Thomas🇬🇧

   A systematic study of neutron-hole strength in the N = 81 nuclei 137Ba, 139Ce, 141Nd and 143Sm is reported. The single-neutron removal reactions (p,d) and (3He,4He) were measured at energies of 23 and 34 MeV, respectively. Spectroscopic factors were extracted from measured cross sections through a distorted-wave Born approximation analysis and centroids of single-particle strength have been established. The change in these centroid energies as a function of proton number have been compared to calculations of the monopole shift for the s1/2 and h11/2 orbitals, where the majority of the strength has been observed. Significant fragmentation of strength was observed for the d and g7/2 orbitals, particularly for the latter orbital which is deeply bound, with summed strengths that indicate a significant amount lies outside of the measured excitation energy range.

   nucl-exPRC(2020)·4 citations
2. 02*

   Modern and Future Colliders

   Vladimir Shiltsev🇺🇸 · Frank Zimmermann🇨🇭

   Since the initial development of charged particle colliders in the middle of the 20th century, these advanced scientific instruments have been at the forefront of scientific discoveries in high energy physics. Collider accelerator technology and beam physics have progressed immensely and modern facilities now operate at energies and luminosities many orders of magnitude greater than the pioneering colliders of the early 1960s. In addition, the field of colliders remains extremely dynamic and continues to develop many innovative approaches. Indeed, several novel concepts are currently being considered for designing and constructing even more powerful future colliders. In this paper, we first review the colliding beam method and the history of colliders, and then present the major achievements of operational machines and the key features of near-term collider projects that are currently under development. We conclude with an analysis of numerous proposals and studies for far-future colliders. The evaluation of their respective potentials reveals tantalizing prospects for further significant breakthroughs in the collider field.

   ↳ physics.acc-phhep-exnucl-exRMP(2021)·187 citations
3. 03*

   Next-to-leading order QCD predictions for dijet photoproduction in lepton-nucleus scattering at the future EIC and at possible LHeC, HE-LHeC, and FCC facilities

   V. Guzey (St. Petersburg, INP)🇷🇺 · M. Klasen (Muenster U., ITP)🇩🇪

   We calculate cross sections for inclusive dijet photoproduction in electron-nucleus scattering in the kinematics of the future EIC and the possible LHeC, HE-LHeC, and the FCC using next-to-leading order (NLO) perturbative QCD and nCTEQ15 and EPPS16 nuclear parton density functions (nPDFs). We make predictions for distributions in the dijet average transverse momentum ${\bar{p}}_T$, the average rapidity $\bar{\eta }$, the observed nuclear momentum fraction $x_A^{\mathrm{obs}}$, and the observed photon momentum fraction $x_{\gamma }^{\mathrm{obs}}$. Comparing the kinematic reaches of the four colliders, we find that an increase of the collision energy from the EIC to the LHeC and beyond extends the coverage in all four considered variables. Notably, the LHeC and HE-LHeC will allow one to probe the dijet cross section down to $x_A^{\mathrm{obs}}\sim 10^{-4}$ (down to $x_A^{\mathrm{obs}}\sim 10^{-5}$ at the FCC). The ratio of the dijet cross sections on a nucleus and the proton, ${\sigma }_A/(A{\sigma }_p)$, depends on $x_A^{\mathrm{obs}}$ in a similar way as the ratio of gluon densities, $g_A(x_A,{\mu }^2)/[A{g}_p(x_A,{\mu }^2)]$, for which current nPDFs predict a strong suppression due to nuclear shadowing in the region $x_A^{\mathrm{obs}}<0.01$. Dijet photoproduction at future lepton-nucleus colliders can therefore be used to test this prediction and considerably reduce the current uncertainties of nPDFs.

   ↳ hep-phhep-exnucl-exPRC(2020)·12 citations
4. 04*

   Kaonic Hydrogen and Deuterium in Hamiltonian Effective Field Theory

   Zhan-Wei Liu🇨🇳 · Jia-Jun Wu🇨🇳 · Derek B. Leinweber🇦🇺 · Anthony W. Thomas🇦🇺

   The anti-kaon nucleon scattering lengths resulting from a Hamiltonian effective field theory analysis of experimental data and lattice QCD studies are presented. The same Hamiltonian is then used to compute the scattering length for the $K^{-}d$ system, taking careful account of the effects of recoil on the energy at which the $\bar{K}N$ T-matrices are evaluated. These results are then used to estimate the shift and width of the $1S$ levels of anti-kaonic hydrogen and deuterium. The $K^{-}p$ result is in excellent agreement with the SIDDHARTA measurement. In the $K^{-}d$ case the imaginary part of the scattering length and consequently the width of the $1S$ state are considerably larger than found in earlier work. This is a consequence of the effect of recoil on the energy of the $\bar{K}N$ energy, which enhances the role of the $\Lambda (1405)$ resonance.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2020)·24 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.