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.
|
Wang, W. F., Feijoo, A., Song, J., & Oset, E. (2022). Molecular Omega(ce), Omega(bb), and Omega(bc) states. Phys. Rev. D, 106(11), 116004–14pp.
Abstract: We study the interaction of meson-baryon coupled channels carrying quantum numbers of a Omega(ce), Omega(bb), and Omega(bc) presently under investigation by the LHCb Collaboration. The interaction is obtained from an extension of the local hidden gauge approach to the heavy quark sector that has proved to provide accurate results compared to experiment in the case of Omega(c), Xi(c) states and pentaquarks, P-c and P-cs. We obtain many bound states, with small decay widths within the space of the chosen coupled channels. The spin-parity of the states are J(P) = 1/2(-) for coupled channels of pseudoscalar-baryon (1/2(+)), J(P) = 3/2(-) for the case of pseudoscalar-baryon (3/2(+)), J(P) = 1/2(-), 3/2(-) for the case of vector-baryon (1/2(+)) and J(P) = 1/2(-), 3/2(-). 5/2(-) for the vector- baryon (3/2(+)) channels. We look for poles of the states and evaluate the couplings to the different channels. The couplings obtained for the open channels can serve as a guide to see in which reaction the obtained states are more likely to be observed.
|
Kim, J. S., Lopez-Fogliani, D. E., Perez, A. D., & Ruiz de Austri, R. (2022). The new (g-2)(mu) and right-handed sneutrino dark matter. Nucl. Phys. B, 974, 115637–23pp.
Abstract: In this paper we investigate the (g – 2)(mu) discrepancy in the context of the R-parity conserving next-to minimal supersymmetric Standard Model plus right-handed neutrinos superfields. The model has the ability to reproduce neutrino physics data and includes the interesting possibility to have the right-handed sneutrino as the lightest supersymmetric particle and a viable dark matter candidate. Since right-handed sneutrinos are singlets, no new contributions for delta a(mu) with respect to the MSSM and NMSSM are present. However, the possibility to have the right-handed sneutrino as the lightest supersymmetric particle opens new ways to escape Large Hadron Collider and direct detection constraints. In particular, we find that dark matter masses within 10 less than or similar to m((upsilon) over tildeR) less than or similar to 600 GeV are fully compatible with current experimental constraints. Remarkably, not only spectra with light sleptons are needed, but we obtain solutions with m((mu) over tilde) greater than or similar to 600 GeV in the entire dark matter mass range that could be probed by new (g – 2)(mu) data in the near future. In addition, dark matter direct detection experiments will be able to explore a sizable portion of the allowed parameter space with mvR < 300 GeV, while indirect detection experiments will be able to probe a much smaller fraction within 200 less than or similar to m((nu)over tilde>R) less than or similar to 350 GeV.
|
Das, A., & Mandal, S. (2021). Bounds on the triplet fermions in type-III seesaw and implications for collider searches. Nucl. Phys. B, 966, 115374–33pp.
Abstract: Type-III seesaw is a simple extension of the Standard Model (SM) with the SU(2)(L) triplet fermion with zero hypercharge. It can explain the origin of the tiny neutrino mass and flavor mixing. After the electroweak symmetry breaking the light neutrino mass is generated by the seesaw mechanism which further ensures the mixings between the light neutrino and heavy neutral lepton mass eigenstates. If the triplet fermions are around the electroweak scale having sizable mixings with the SM sector allowed by the correct gauge symmetry, they can be produced at the high energy colliders leaving a variety of characteristic signatures. Based on a simple and concrete realizations of the model we employ a general parametrization for the neutrino Dirac mass matrix and perform a parameter scan to identify the allowed regions satisfying the experimental constraints from the neutrino oscillation data, the electroweak precision measurements and the lepton-flavor violating processes, respectively considering the normal and inverted neutrino mass hierarchies. These parameter regions can be probed at the different collider experiments.
|
Bombacigno, F., Boudet, S., & Montani, G. (2021). Generalized Ashtekar variables for Palatini f(R) models. Nucl. Phys. B, 963, 115281–21pp.
Abstract: We consider special classes of Palatini f(R) theories, featured by additional Loop Quantum Gravity inspired terms, with the aim of identifying a set of modified Ashtekar canonical variables, which still preserve the SU(2) gauge structure of the standard theory. In particular, we allow for affine connection to be endowed with torsion, which turns out to depend on the additional scalar degree affecting Palatini f( R) gravity, and in this respect we successfully construct a novel Gauss constraint. We analyze the role of the additional scalar field, outlining as it acquires a dynamical character by virtue of a non vanishing Immirzi parameter, and we describe some possible effects on the area operator stemming from such a revised theoretical framework. Finally, we compare our results with earlier studies in literature, discussing differences between metric and Palatini approaches. It is worth noting how the Hamiltonian turns out to be different in the two cases. The results can be reconciled when the analysis is performed in the Einstein frame.
|
Miralles, V., & Pich, A. (2019). LHC bounds on colored scalars. Phys. Rev. D, 100(11), 115042–11pp.
Abstract: We analyze the constraints on colored scalar bosons imposed by the current LHC data at root s = 13 TeV. Specifically, we consider an additional electroweak doublet of color-octet scalars, satisfying the principle of minimal flavor violation in order to fulfill the stringent experimental limits on flavor-changing neutral currents. We demonstrate that colored scalars with masses below 800 GeV are already excluded, provided they are not fermiophobic.
|
Masud, M., Roy, S., & Mehta, P. (2019). Correlations and degeneracies among the NSI parameters with tunable beams at DUNE. Phys. Rev. D, 99(11), 115032–19pp.
Abstract: The Deep Underground Neutrino Experiment (DUNE) is a leading experiment in neutrino physics which is presently under construction. DUNE aims to measure the yet unknown parameters in the three flavor oscillation scenario which includes discovery of leptonic CP violation, determination of the mass hierarchy and determination of the octant of theta(23). Additionally, the ancillary goals of DUNE include probing the subdominant effects induced by new physics. A widely studied new physics scenario is that of nonstandard neutrino interactions (NSI) in propagation which impacts the oscillations of neutrinos. We consider some of the essential NSI parameters impacting the oscillation signals at DUNE and explore the space of NSI parameters as well as study their correlations among themselves and with the yet unknown CP violating phase, delta appearing in the standard paradigm. The experiment utilizes a wide band beam and provides us with a unique opportunity to utilize different beam tunes at DUNE. We demonstrate that combining information from different beam tunes (low energy and medium energy) available at DUNE impacts the ability to probe some of these parameters and leads to altering the allowed regions in two-dimensional space of parameters considered.
|
Mandal, S., Srivastava, R., & Valle, J. W. F. (2020). Consistency of the dynamical high-scale type-I seesaw mechanism. Phys. Rev. D, 101(11), 115030–15pp.
Abstract: We analyze the consistency of electroweak breaking within the simplest high-scale SU(3)(c) circle times SU(2)(L) circle times U(1)(Y) type-I seesaw mechanism. We derive the full two-loop renormalization group equations of the relevant parameters, including the quartic Higgs self-coupling of the Standard Model. For the simplest case of bare “right-handed” neutrino mass terms we find that, with large Yukawa couplings, the Higgs quartic self-coupling becomes negative much below the seesaw scale, so that the model may be inconsistent even as an effective theory. We show, however, that the “dynamical” type-I high-scale seesaw with spontaneous lepton number violation has better stability properties.
|
Das, A., Bhupal Dev, P. S., Hosotani, Y., & Mandal, S. (2022). Probing the minimal U(1)(X) model at future electron positron colliders via fermion pair-production channels. Phys. Rev. D, 105(11), 115030–28pp.
Abstract: The minimal U(1)(X) extension of the Standard Model (SM) is a well-motivated new physics scenario, where anomaly cancellation dictates new neutral gauge boson (Z') couplings with the SM fermions in terms of the U(1)(X) charges of the new scalar fields. We investigate the SM charged fermion pair-production process for different values of these U(1)(X) charges at future e(-)e(+) colliders: e(+)e(-) -> f (f) over bar Apart from the standard gamma and Z-mediated processes, this model features additional s-channel (or both s and t-channel when f = e(-)) Z' exchange which interferes with the SM processes. We first estimate the bounds on the U(1)(X) coupling (g') and the Z' mass (M-Z') considering the latest dilepton and dijet constraints from the heavy resonance searches at the LHC. Then using the allowed values of g', we study the angular distributions, forward-backward (A(FB)), left-right (A(LB)), and left-right forward-backward (A(LR-FB)) asymmetries of the final states. We fmd that these observables can show substantial deviations from the SM results in the U(1)(X) model, thus providing a powerful probe of the multi-TeV Z' bosons at future e(+)e(-) colliders.
|
Carquin, E., Neill, N. A., Helo, J. C., & Hirsch, M. (2019). Exotic colored fermions and lepton number violation at the LHC. Phys. Rev. D, 99(11), 115028–9pp.
Abstract: Majorana neutrino mass models with a scale of lepton number violation of order tem-electron-volts potentially lead to signals at the LHC. Here, we consider an extension of the standard model with a colored octet fermion and a scalar leptoquark. This model generates neutrino masses at two-loop order. We make a detailed Monte Carlo study of the lepton number violating signal at the LHC in this model, including a simulation of standard model backgrounds. Our forecast predicts that the LHC with 300/fb should be able to probe this model up to color-octet fermion masses in the range of (2.6-2.7) TeV, depending on the lepton flavor of the final state.
|