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Beltran, R., Cottin, G., Helo, J. C., Hirsch, M., Titov, A., & Wang, Z. S. (2022). Long-lived heavy neutral leptons at the LHC: four-fermion single-N-R operators. J. High Energy Phys., 01(1), 044–18pp.
Abstract: Interest in searches for heavy neutral leptons (HNLs) at the LHC has increased considerably in the past few years. In the minimal scenario, HNLs are produced and decay via their mixing with active neutrinos in the Standard Model (SM) spectrum. However, many SM extensions with HNLs have been discussed in the literature, which sometimes change expectations for LHC sensitivities drastically. In the N-R SMEFT, one extends the SM effective field theory with operators including SM singlet fermions, which allows to study HNL phenomenology in a “model independent” way. In this paper, we study the sensitivity of ATLAS to HNLs in the N-R SMEFT for four-fermion operators with a single HNL. These operators might dominate both production and decay of HNLs, and we find that new physics scales in excess of 20 TeV could be probed at the high-luminosity LHC.
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Bernabeu, J., Botella, F. J., Nebot, M., & Segarra, A. (2022). B-0 – (B)over-bar(0) entanglement for an ideal experiment for the direct CP violation phi(3)/gamma phase. Phys. Rev. D, 106(5), 054026–7pp.
Abstract: B-0-(B) over bar0 entanglement offers a conceptual alternative to the single charged B-decay asymmetry for the measurement of the direct CP-violating gamma/phi(3) phase. With f = J/Psi(L); J/Psi K-S and g = (pi pi)(0); (rho(L)rho(L))(0), the 16 time-ordered double-decay rate intensities to (f, g) depend on the relative phase between the f- and g-decay amplitudes given by gamma at tree level. Several constraining consistencies appear. An intrinsic accuracy of the method at the level of +/- 1 degrees could be achievable at Belle-II with an improved determination of the penguin amplitude to g channels from existing facilities.
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Bernabeu, J., & Di Domenico, A. (2022). Can future observation of the living partner post-tag the past decayed state in entangled neutral K mesons? Phys. Rev. D, 105(11), 116004–8pp.
Abstract: Entangled neutral K mesons allow for the study of their correlated dynamics at interference and decoherence times not accessible in any other system. We find novel quantum phenomena associated to a correlation in time between the two partners: The past state of the first decayed kaon, when it was entangled before its decay, is post-tagged by the result and the time of the future observation of the second decay channel. This surprising “from future to past” effect is fully observable and leads to the unique experimental tag of the K-S state, an unsolved problem since the discovery of CP violation.
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Bernal, N., Munoz-Albornoz, V., Palomares-Ruiz, S., & Villanueva-Domingo, P. (2022). Current and future neutrino limits on the abundance of primordial black holes. J. Cosmol. Astropart. Phys., 10(10), 068–38pp.
Abstract: Primordial black holes (PBHs) formed in the early Universe are sources of neutrinos emitted via Hawking radiation. Such astrophysical neutrinos could be detected at Earth and constraints on the abundance of comet-mass PBHs could be derived from the null observation of this neutrino flux. Here, we consider non-rotating PBHs and improve constraints using Super-Kamiokande neutrino data, as well as we perform forecasts for next-generation neutrino (Hyper-Kamiokande, JUNO, DUNE) and dark matter (DARWIN, ARGO) detectors, which we compare. For PBHs less massive than " few x 1014 g, PBHs would have already evaporated by now, whereas more massive PBHs would still be present and would constitute a fraction of the dark matter of the Universe. We consider monochromatic and extended (log-normal) mass distributions, and a PBH mass range spanning from 1012 g to ti 1016 g. Finally, we also compare our results with previous ones in the literature.
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Bernigaud, J., Blanke, M., de Medeiros Varzielas, I., Talbert, J., & Zurita, J. (2022). LHC signatures of tau-flavoured vector leptoquarks. J. High Energy Phys., 08(8), 127–31pp.
Abstract: We consider the phenomenological signatures of Simplified Models of Flavourful Leptoquarks, whose Beyond-the-Standard Model (SM) couplings to fermion generations occur via textures that are well motivated from a broad class of ultraviolet flavour models (which we briefly review). We place particular emphasis on the study of the vector leptoquark Delta(mu) with assignments (3, 1, 2/3) under the SM's gauge symmetry, SU(3)(C) x SU(2)(L) x U(1)(Y), which has the tantalising possibility of explaining both R-K(*) and R-D(*) anomalies. Upon performing global likelihood scans of the leptoquark's coupling parameter space, focusing in particular on models with tree-level couplings to a single charged lepton species, we then provide confidence intervals and benchmark points preferred by low(er)-energy flavour data. Finally, we use these constraints to further evaluate the (promising) Large Hadron Collider (LHC) detection prospects of pairs of tau-flavoured Delta(mu), through their distinct (a)symmetric decay channels. Namely, we consider direct third-generation leptoquark and jets plus missing-energy searches at the LHC, which we find to be complementary. Depending on the simplified model under consideration, the direct searches constrain the Delta(mu), mass up to 1500-1770 GeV when the branching fraction of Delta(mu), is entirely to third-generation quarks (but are significantly reduced with decreased branching ratios to the third generation), whereas the missing-energy searches constrain the mass up to 1150-1700 GeV while being largely insensitive to the third-generation branching fraction.
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Bhattacharya, S., Sil, A., Roshan, R., & Vatsyayan, D. (2022). Symmetry origin of baryon asymmetry, dark matter, and neutrino mass. Phys. Rev. D, 106(7), 075005–10pp.
Abstract: We propose a minimal model based on lepton number symmetry (and violation), to address a common origin of baryon asymmetry, dark matter and neutrino mass generation. The model consists of a vectorlike fermion to constitute the dark sector, three right-handed neutrinos (RHNs) to dictate leptogenesis and neutrino mass, while an additional complex scalar is assumed to be present in the early Universe the decay of which produces both dark matter and RHNs via lepton number violating and lepton number conserving interactions respectively. Interestingly, the presence of the same scalar helps in making the electroweak vacuum stable until the Planck scale. The unnatural largeness and smallness of the parameters required to describe correct experimental limits are attributed to lepton number violation. The allowed parameter space of the model is illustrated via a numerical scan.
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Biagi, N., Francesconi, S., Gessner, M., Bellini, M., & Zavatta, A. (2022). Remote Phase Sensing by Coherent Single Photon Addition. Adv. Quantum Technol., 5(12), 2200039–9pp.
Abstract: A remote phase sensing scheme is proposed, inspired by the high sensitivity of the entanglement produced by coherent multimode photon addition on the phase set in the remote heralding apparatus. By exploring the case of delocalized photon addition over two modes containing identical coherent states, the optimal observable to perform remote phase estimation from heralded quadrature measurements is derived. The technique is experimentally tested with calibration measurements and then used for estimating a remote phase with a sensitivity that is found to scale with the intensity of the local coherent states, which never interacted with the sample.
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Biryukov, V. M., & Ruiz Vidal, J. (2022). Improved experimental layout for dipole moment measurements at the LHC. Eur. Phys. J. C, 82(2), 149–11pp.
Abstract: The electric and magnetic dipole moment of charm and bottom baryons can be measured for the first time by using bent crystal technology at the LHC. The experimental method, proposed in recent years, suffers from limited statistics, which dominates the uncertainty of the measurement. In this work, we present an alternative experimental layout, based on the use of crystal lenses, that improves the trapping efficiency by about a factor 15 (35) for a 2-cm (5-mm) target with respect to the nominal layout, with plain crystal faces. The efficiencies are evaluated taking into account the constraints from the LHC machine, and the technical challenges to realize this novel experimental method are discussed.
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Blanton, T. D., Romero-Lopez, F., & Sharpe, S. R. (2022). Implementing the three-particle quantization condition for pi(+)pi K-+(+) and related systems. J. High Energy Phys., 02(2), 098–49pp.
Abstract: Recently, the formalism needed to relate the finite-volume spectrum of systems of nondegenerate spinless particles has been derived. In this work we discuss a range of issues that arise when implementing this formalism in practice, provide further theoretical results that can be used to check the implementation, and make available codes for implementing the three-particle quantization condition. Specifically, we discuss the need to modify the upper limit of the cutoff function due to the fact that the left-hand cut in the scattering amplitudes for two nondegenerate particles moves closer to threshold; we describe the decomposition of the three-particle amplitude K-df,K-3 into the matrix basis used in the quantization condition, including both s and p waves, with the latter arising in the amplitude for two nondegenerate particles; we derive the threshold expansion for the lightest three-particle state in the rest frame up to O(1/L-5); and we calculate the leading-order predictions in chiral perturbation theory for K-df,K-3 in the pi(+)pi K-+(+) and pi+K+K+ systems. We focus mainly on systems with two identical particles plus a third that is different (“2+1” systems). We describe the formalism in full detail, and present numerical explorations in toy models, in particular checking that the results agree with the threshold expansion, and making a prediction for the spectrum of pi(+)pi K-+(+) levels using the two- and three-particle interactions predicted by chiral perturbation theory.
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Bonilla, J. et al, & Vos, M. (2022). Jets and Jet Substructure at Future Colliders. Front. Physics, 10, 897719–17pp.
Abstract: Even though jet substructure was not an original design consideration for the Large Hadron Collider (LHC) experiments, it has emerged as an essential tool for the current physics program. We examine the role of jet substructure on the motivation for and design of future energy Frontier colliders. In particular, we discuss the need for a vibrant theory and experimental research and development program to extend jet substructure physics into the new regimes probed by future colliders. Jet substructure has organically evolved with a close connection between theorists and experimentalists and has catalyzed exciting innovations in both communities. We expect such developments will play an important role in the future energy Frontier physics program.
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