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Beltran, R., Günther, J., Hirsch, M., Titov, A., & Wang, Z. S. (2024). Heavy neutral leptons from kaons in effective field theory. Phys. Rev. D, 109(11), 115014–19pp.
Abstract: In the framework of the low -energy effective theory containing, in addition to the Standard -Model fields, heavy neutral leptons (HNLs), we compute the decay rates of neutral and charged kaons into HNLs. We consider both lepton -number -conserving and lepton -number -violating four-fermion operators, taking into account also the contribution of active -heavy neutrino mixing. Assuming that the produced HNLs are longlived, we perform simulations and calculate the sensitivities of future long -lived -particle (LLP) detectors at the high -luminosity LHC as well as the near detector of the Deep Underground Neutrino Experiment (DUNE -ND) to the considered scenario. When applicable, we also recast the existing bounds on the minimal mixing case obtained by NA62, T2K, and PS191. Our findings show that, while the future LHC LLP detectors can probe currently allowed parameter space only in certain benchmark scenarios, DUNE -ND should be sensitive to parameter space beyond the current bounds in almost all the benchmark scenarios, and, for some of the effective operators considered, it can even probe new -physics scales in excess of 3000 TeV.
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Aristizabal Sierra, D., De Romeri, V., & Ternes, C. A. (2024). Reactor neutrino background in next-generation dark matter detectors. Phys. Rev. D, 109(11), 115026–7pp.
Abstract: Third -generation dark matter detectors will be fully sensitive to the 8 B solar neutrino flux. Because of this, the characterization of such a background has been the subject of extensive analyses over the last few years. In contrast, little is known about the impact of reactor neutrinos. In this paper, we report on the implications of such a flux for dark matter direct -detection searches. We consider five potential detector deployment sites envisioned by the recently established XLZD Consortium: SURF, SNOLAB, Kamioka, LNGS, and Boulby. By using public reactor data, we construct five reactor clusters -involving about 100 currently operating commercial nuclear reactors each -and determine the net neutrino flux at each detector site. Assuming a xenon -based detector and a 50 ton -year exposure, we show that in all cases the neutrino event rate may be sizable, depending on energy recoil thresholds. Of all possible detector sites, SURF and LNGS are those with the smallest reactor neutrino background. On the contrary, SNOLAB and Boulby are subject to the strongest reactor neutrino fluxes, with Kamioka being subject to a more moderate background. Our findings demonstrate that reactor neutrino fluxes should be taken into account in the next round of dark matter searches. We argue that this background may be particularly relevant for directional detectors, provided they meet the requirements we have employed in this analysis.
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Alkofer, R., Llanes-Estrada, F. J., & Salas-Bernardez, A. (2024). Spinning pairs: Supporting 3P0 quark-pair creation from Landau-gauge Green's functions. Phys. Rev. D, 109(7), 074015–21pp.
Abstract: Abundant phenomenology suggests that strong decays from relatively low-excitation hadrons into other hadrons proceed by the creation of a light quark-antiquark pair with zero total angular momentum, the so called 3P0 mechanism originating from a scalar bilinear. Yet the quantum chromodynamics (QCD) interaction is perturbatively mediated by gluons of spin one, and QCD presents a chirally symmetric Lagrangian. Such scalar decay term must be spontaneously generated upon breaking chiral symmetry. We attempt to reproduce this with the help of the quark-gluon vertex in Landau gauge, whose nonperturbative structure has been reasonably elucidated in the last years, and insertions of a uniform, constant chromoelectric field. This is akin to Schwinger pair production in quantum electrodynamics (QED), and we provide a comparison with its two field-insertions diagram. We find that, the symmetry being cylindrical, the adequate quantum numbers to discuss the production are rather 3E0, 3E1, and 3110 as in diatomic molecules, and we indeed find a sizeable contribution of the third decay mechanism, which may give a rationale for the 3P0 phenomenology, as long as the momentum of the produced pair is at or below the scale of the bare or dynamically generated fermion mass. On the other hand, ultrarelativistic fermions are rather ejected with 3E1 quantum numbers. In QED, our results suggest that 3E0 dominates, whereas the constraint of producing a color singlet in QCD leads to 3110 dominance at sub-GeV momenta.
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Chatterjee, S. S., Lavignac, S., Miranda, O. G., & Sanchez Garcia, G. (2023). Constraining nonstandard interactions with coherent elastic neutrino-nucleus scattering at the European Spallation Source. Phys. Rev. D, 107(5), 055019–17pp.
Abstract: The European Spallation Source (ESS), currently under construction in Sweden, will provide an intense pulsed neutrino flux allowing for high-statistics measurements of coherent elastic neutrino-nucleus scattering (CEvNS) with advanced nuclear recoil detectors. In this paper, we investigate in detail the possibility of constraining nonstandard neutrino interactions (NSIs) through such precision CEvNS measurements at the ESS, considering the different proposed detection technologies, either alone or in combination. We first study the sensitivity to neutral-current NSI parameters that each detector can reach in 3 years of data taking. We then show that operating two detectors simultaneously can significantly improve the expected sensitivity on flavor-diagonal NSI parameters. Combining the results of two detectors turns out to be even more useful when two NSI parameters are assumed to be nonvanishing at a time. In this case, suitably chosen detector combinations can reduce the degeneracies between some pairs of NSI parameters to a small region of the parameter space.
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Ikeno, N., Bayar, M., & Oset, E. (2023). Molecular states of D*D*Kbar* nature. Phys. Rev. D, 107(3), 034006–12pp.
Abstract: We study the interaction of two D* and a over bar K* by using the fixed center approximation to the Faddeev equations to search for bound states of the three-body system. Since the D*D* interaction is attractive and gives a bound state, and so is the case of the D* over bar K* interaction, where the JP = 0+ bound state is identified with the X0(2900), the D*D* over bar K* system leads to manifestly exotic bound states with ccs open quarks. We obtain bound states of isospin I = 1=2, negative parity and total spin J = 0, 1, 2. For J = 0 we obtain one state, and for J = 1, 2 we obtain two states in each case. The binding energies range from 56 to 152 MeV and the widths from 80 to 100 MeV.
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Bayar, M., Feijoo, A., & Oset, E. (2023). X(3960) seen in Ds plus Ds- as the X(3930) state seen in D plus D. Phys. Rev. D, 107(3), 034007–5pp.
Abstract: We perform a calculation of the interaction of the D over bar D, Ds over bar Ds coupled channels and find two bound states, one coupling to DD over bar and another one at higher energies coupling mostly to D+s D-s . We identify this latter state with the X0(3930) seen in the D+D- mass distribution in the B+ -D+D-K+ decay, and also show that it produces an enhancement of the D+s D-s mass distribution close to threshold which is compatible with the recent LHCb observation in the B+ -D+s D-s K+ decay which has been identified as a new state, X0(3960).
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Braaten, E., Bruschini, R., He, L. P., Ingles, K., & Jiang, J. (2023). Evolution of charm-meson ratios in an expanding hadron gas. Phys. Rev. D, 107(7), 076006–6pp.
Abstract: We study the time evolution of the numbers of charm mesons after the kinetic freeze-out of the hadron gas produced by a central heavy-ion collision. The pi D* -> pi D* reaction rates have t-channel singularities that give contributions inversely proportional to the thermal width of the D. The ratio of the D0 and D+ production rates can differ significantly from those predicted using the measured D* branching fractions.
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Dreiner, H. K., Martin Lozano, V., Nangia, S., & Opferkuch, T. (2023). Lepton PDFs and multipurpose single-lepton searches at the LHC. Phys. Rev. D, 107(3), 035011–12pp.
Abstract: A final state consisting of one charged lepton, at least one jet, and little missing transverse energy can be a very promising signature of new physics at the LHC across a wide range of models. However, it has received only limited attention so far. In this work we discuss the potential sensitivity of this channel to various new physics scenarios. To demonstrate our point, we consider its application to lepton parton distribution functions (PDFs) at the LHC in the context of supersymmetry. These lepton PDFs can lead to resonant squark production (similar to leptoquarks) via lepton number violating couplings present in R-parity violating supersymmetry (RPV-SUSY). Unlike leptoquarks, in RPV-SUSY there are many possible decay modes leading to a wide range of signatures. We propose two generic search regions: (a) a single first or second generation charged lepton, exactly 1 jet and low missing transverse energy, and (b) a single first or second generation charged lepton, at least 3 jets, and low missing transverse energy. We demonstrate that together these cover a large range of RPV-SUSY signatures, and have the potential to perform better than existing low-energy bounds, while being general enough to extend to a wide range of possible models hitherto not explored at the LHC.
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De Romeri, V., Nava, J., Puerta, M., & Vicente, A. (2023). Dark matter in the scotogenic model with spontaneous lepton number violation. Phys. Rev. D, 107(9), 095019–11pp.
Abstract: Scotogenic models constitute an appealing solution to the generation of neutrino masses and to the dark matter mystery. In this work we consider a version of the scotogenic model that breaks the lepton number spontaneously. At this scope, we extend the particle content of the scotogenic model with an additional singlet scalar which acquires a nonzero vacuum expectation value and breaks a global lepton number symmetry. As a consequence, a massless Goldstone boson, the majoron, appears in the particle spectrum. We discuss how the presence of the majoron modifies the phenomenology, both in flavor and dark matter observables. We focus on the fermionic dark matter candidate and analyze its relic abundance and prospects for both direct and indirect detection.
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Villanueva-Domingo, P., Villaescusa-Navarro, F., Genel, S., Angles-Alcazar, D., Hernquist, L., Marinacci, F., et al. (2023). Weighing the Milky Way and Andromeda galaxies with artificial intelligence. Phys. Rev. D, 107(10), 103003–8pp.
Abstract: We present new constraints on the masses of the halos hosting the Milky Way and Andromeda galaxies derived using graph neural networks. Our models, trained on 2,000 state-of-the-art hydrodynamic simulations of the CAMELS project, only make use of the positions, velocities and stellar masses of the galaxies belonging to the halos, and are able to perform likelihood-free inference on halo masses while accounting for both cosmological and astrophysical uncertainties. Our constraints are in agreement with estimates from other traditional methods, within our derived posterior standard deviation.
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