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Molina, R., & Oset, E. (2023). T-cS (2900) as a threshold effect from the interaction of the D* K *, D *(s)rho channels. Phys. Rev. D, 107(5), 056015–7pp.
Abstract: We look at the mass distribution of the D(S)(+)i Pi(-) In the B-0 ->(DDS+)-D-0 Pi(-)decay, where a peak has been observed in the region of the D (*) (s)rho, D* K* thresholds. By creating these two channels together with a D (0) in B-0 decay and letting them interact as coupled channels, we obtain a structure around their thresholds, short of producing a bound state, which leads to a peak in the D-S(+) Pi(-)mass distribution in the B-0 -> (DDS+)-D-0 Pi(-)decay. We conclude that the interaction between the D*K* and D (*) (s)rho is essential to produce the cusp structure that we associate to the recently seen Tcs(2900), and that its experimental width is mainly due to the decay width of the rho meson. The peak obtained together with a smooth background reproduces fairly well the experimental mass distribution observed in the B (0)-> (DDS+)-D-0 Pi(-) decay.
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Pedersen, L. G. et al, & Morales, A. I. (2023). First spectroscopic study of odd-odd 78Cu. Phys. Rev. C, 107(4), 044301–10pp.
Abstract: Nuclei in the vicinity of 78Ni are important benchmarks for nuclear structure, which can reveal changes in the shell structure far from stability. Spectroscopy of the odd-odd isotope 78Cu was performed for the first time in an experiment with the EURICA setup at the Radioactive Isotope Beam Factory at RIKEN Nishina Center. Excited states in the neutron-rich isotope were populated following the beta decay of 78Ni produced by in-flight fission and and separated by the BigRIPS separator. A level scheme based on the analysis of γ−γ coincidences is presented. Tentative spin and parity assignments were made when possible based on the β-decay feeding intensities and γ-decay properties of the excited states. Time correlations between β and γ decay show clear indications of an isomeric state with a half-life of 3.8(4) ms. Large-scale Monte Carlo shell-model calculations were performed using the A3DA-m interaction and a valence space comprising the full fp shell and the 1g9/2 and 2d5/2 orbitals for both protons and neutrons. The comparison of the experimental results with the shell-model calculations allows interpreting the excited states in terms of spin multiplets arising from the proton-neutron interaction. The results provide further insight into the evolution of the proton single-particle orbitals as a function of neutron number, and quantitative information about the proton-neutron interaction outside the doubly magic 78Ni core.
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Dutka, T. P., & Gargalionis, J. (2023). Dimension-five baryon-number violation in low-scale Pati-Salam models. Phys. Rev. D, 107(3), 035019–10pp.
Abstract: The gauge bosons of the Pati-Salam model do not mediate proton decay at the renormalizable level, and for this reason it is possible to construct scenarios in which SU(4) (R) SU(2)R is broken at relatively low scales. In this paper we show that such low-scale models generate dimension-five operators that can give rise to nucleon decays at unacceptably large rates, even if the operators are suppressed by the Planck scale. We find an interesting complementarity between the nucleon-decay limits and the usual meson-decay constraints. Furthermore, we argue that these operators are generically present when the model is embedded into SO(10), lowering the suppression scale. Under reasonable assumptions, the lower limit on the breaking scale can be constrained to be as high as O(108) GeV.
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Nadal-Gisbert, S., Navarro-Salas, J., & Pla, S. (2023). Low-energy states and CPT invariance at the big bang. Phys. Rev. D, 107(8), 085018–16pp.
Abstract: In this paper, we analyze the quantum vacuum in a radiation-dominated and CPT -invariant universe by further imposing the quantum states to be ultraviolet regular i.e., satisfying the Hadamard/adiabatic condition. For scalar fields, this is enforced by constructing the vacuum via the states of low-energy proposal. For spin -12 fields, we extend this proposal for a FLRW spacetime and apply it for the radiation-dominated and CPT -invariant universe. We focus on minimizing the smeared energy density around the big bang and give strong evidence that the resulting states satisfy the Hadamard/adiabatic condition. These states are then self -consistent candidates as effective big bang quantum vacuum from the field theory perspective.
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DUNE Collaboration(Abud, A. A. et al), Amedo, P., Antonova, M., Barenboim, G., Cervera-Villanueva, A., De Romeri, V., et al. (2023). Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector. Phys. Rev. D, 107(9), 092012–22pp.
Abstract: Measurements of electrons from ?e interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection, and solar neutrino measurements. This article describes the selection and reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector. ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and operated at CERN as a charged particle test beam experiment. A sample of low-energy electrons produced by the decay of cosmic muons is selected with a purity of 95%. This sample is used to calibrate the low-energy electron energy scale with two techniques. An electron energy calibration based on a cosmic ray muon sample uses calibration constants derived from measured and simulated cosmic ray muon events. Another calibration technique makes use of the theoretically well-understood Michel electron energy spectrum to convert reconstructed charge to electron energy. In addition, the effects of detector response to low-energy electron energy scale and its resolution including readout electronics threshold effects are quantified. Finally, the relation between the theoretical and reconstructed low-energy electron energy spectra is derived, and the energy resolution is characterized. The low-energy electron selection presented here accounts for about 75% of the total electron deposited energy. After the addition of lost energy using a Monte Carlo simulation, the energy resolution improves from about 40% to 25% at 50 MeV. These results are used to validate the expected capabilities of the DUNE far detector to reconstruct low-energy electrons.
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n_TOF Collaboration(Sosnin, N. V. et al.), Babiano-Suarez, V., Caballero, L., Domingo-Pardo, C., Ladarescu, I., & Tain, J. L. (2023). Measurement of the 77Se(n,gamma) cross section up to 200 keV at the n_TOF facility at CERN. Phys. Rev. C, 107(6), 065805–9pp.
Abstract: The 77Se(n,gamma) reaction is of importance for 77Se abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the 77Se radiative neutron capture cross section at the Neutron Time-of-Flight facility at CERN. Resonance capture kernels were derived up to 51 keV and cross sections up to 200 keV. Maxwellian-averaged cross sections were calculated for stellar temperatures between kT = 5 keV and kT = 100 keV, with uncertainties between 4.2% and 5.7%. Our results lead to substantial decreases of 14% and 19% in 77Se abundances produced through the slow neutron capture process in selected stellar models of 15M0 and 2M0, respectively, compared to using previous recommendation of the cross section.
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n_TOF Collaboration(Tarrío, D. et al), Domingo-Pardo, C., Giubrone, G., & Tain, J. L. (2023). Neutron-induced fission cross sections of Th-232 and U-233 up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility. Phys. Rev. C, 107(4), 044616–21pp.
Abstract: The neutron-induced fission cross sections of Th-232 and U-233 were measured relative to U-235 in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of Th-232, and from 0.7 eV in case of U-233), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (nTOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of U-233, previous results available in EXFOR, whereas in the case of Th-232 these data were obtained from our measurement, using PPACs and targets tilted 45 degrees with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL++ and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those ( p, f) data with our (n, f) data on Th-232 and U-233 and on other isotopes studied earlier at nTOF using the same experimental setup.
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Abreu, L. M., Navarra, F. S., Nielsen, M., & Vieira, H. P. L. (2023). Multiplicity of Z(cs)(3985) in heavy ion collisions. Phys. Rev. D, 107(11), 114013–9pp.
Abstract: Using the coalescence model we compute the multiplicity of Z(cs)(3985)(-) (treated as a compact tetraquark) at the end of the quark gluon plasma phase in heavy ion collisions. Then we study the time evolution of this state in the hot hadron gas phase. We calculate the thermal cross sections for the collisions of the Z(cs)(3985)(-) with light mesons using effective Lagrangians and form factors derived from QCD sum rules for the vertices Z(cs)(D) over bar (s)* D and Z(cs)(D) over bar D-s*. We solve the kinetic equation and find how the Z(cs)(3985)(-) multiplicity is affected by the considered reactions during the expansion of the hadronic matter. A comparison with the statistical hadronization model predictions is presented. Our results show that the tetraquark yield increases by a factor of about 2-3 from the hadronization to the kinetic freeze-out. We also make predictions for the dependence of the Z(cs)(3985)(-) yield on the centrality, the center-of-mass energy and the charged hadron multiplicity measured at midrapidity [dN(ch)/d eta(eta < 0.5)].
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Heavy Flavor Averaging Group(Amhis, Y. et al), & Oyanguren, A. (2023). Averages of b-hadron, c-handron, and t-lepton properties as of 2021. Phys. Rev. D, 107(5), 052008–365pp.
Abstract: This paper reports world averages of measurements of b-hadron, c-hadron, and τ-lepton properties obtained by the Heavy Flavor Averaging Group using results available before April 2021. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays, and Cabibbo-Kobayashi-Maskawa matrix elements.
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ATLAS Collaboration(Aad, G. et al), Amos, K. R., Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Cantero, J., et al. (2023). Production of Upsilon(nS) mesons in Pb plus Pb and pp collisions at 5.02 TeV. Phys. Rev. C, 107(5), 054912–25pp.
Abstract: A measurement of the production of vector bottomonium states, Upsilon(1S), Upsilon(2S), and Upsilon(3S), in Pb + Pb and pp collisions at a center-of-mass energy per nucleon pair of 5.02 TeV is presented. The data correspond to integrated luminosities of 1.38 nb(-1) of Pb + Pb data collected in 2018, 0.44 nb-1 of Pb + Pb data collected in 2015, and 0.26 fb(-1) of pp data collected in 2017 by the ATLAS detector at the Large Hadron Collider. The measurements are performed in the dimuon decay channel for transverse momentum p(T)(mu mu) < 30 GeV, absolute rapidity vertical bar y(mu mu)vertical bar < 1.5, and Pb + Pb event centrality 0-80%. The production rates of the three bottomonium states in Pb + Pb collisions are compared with those in pp collisions to extract the nuclear modification factors as functions of event centrality, p(T)(mu mu), and vertical bar y(mu mu)vertical bar. In addition, the suppression of the excited states relative to the ground state is studied. The results are compared with theoretical model calculations.
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