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Angles-Castillo, A., & Perez, A. (2022). A quantum walk simulation of extra dimensions with warped geometry. Sci Rep, 12(1), 1926–12pp.
Abstract: We investigate the properties of a quantum walk which can simulate the behavior of a spin 1/2 particle in a model with an ordinary spatial dimension, and one extra dimension with warped geometry between two branes. Such a setup constitutes a 1+ 1 dimensional version of the Randall-Sundrum model, which plays an important role in high energy physics. In the continuum spacetime limit, the quantum walk reproduces the Dirac equation corresponding to the model, which allows to anticipate some of the properties that can be reproduced by the quantum walk. In particular, we observe that the probability distribution becomes, at large time steps, concentrated near the “low energy” brane, and can be approximated as the lowest eigenstate of the continuum Hamiltonian that is compatible with the symmetries of the model. In this way, we obtain a localization effect whose strength is controlled by a warp coefficient. In other words, here localization arises from the geometry of the model, at variance with the usual effect that is originated from random irregularities, as in Anderson localization. In summary, we establish an interesting correspondence between a high energy physics model and localization in quantum walks.
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Bandyopadhyay, P., Jangid, S., & Karan, A. (2022). Constraining scalar doublet and triplet leptoquarks with vacuum stability and perturbativity. Eur. Phys. J. C, 82(6), 516–44pp.
Abstract: We investigate the constraints on the leptoquark Yukawa couplings and the Higgs-leptoquark quartic couplings for scalar doublet leptoquark (R) over tilde (2), scalar triplet leptoquark S-3 and their combination with both three generations and one generation with respect to perturbative unitarity and vacuum stability. The perturbative unitarity of all the dimensionless couplings is studied via one- and two-loop beta functions. New SU(2)(L) multiplets in terms of these leptoquarks are introduced to fabricate Landau poles at the two-loop level in the gauge coupling g(2) at 10(19.7) GeV and 10(14.4) GeV, respectively, for the S-3 and (R) over tilde (2) + S-3 models with three generations. However, such Landau poles cease to exist for (R) over tilde (2) and any of these extensions with both one and two generations up to Planck scale. The Higgs-leptoquark quartic couplings acquire severe constraints to protect Planck scale perturbativity, whereas leptoquark Yukawa couplings acquire some upper bound in order to respect Planck scale stability of Higgs vacuum. The Higgs quartic coupling at the two-loop level constrains the leptoquark Yukawa couplings for (R) over tilde (2), S-3, (R) over tilde (2) + S-3 with values less than or similar to 1.30, 3.90, 1.00 with three generations. In the effective potential approach, the presence of any of these leptoquarks with any number of generations pushes the metastable vacuum of the Standard Model to the stable region.
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Huang, G. Y., Lindner, M., Martinez-Mirave, P., & Sen, M. (2022). Cosmology-friendly time-varying neutrino masses via the sterile neutrino portal. Phys. Rev. D, 106(3), 033004–18pp.
Abstract: We investigate a consistent scenario of time-varying neutrino masses, and discuss its impact on cosmology, beta decay, and neutrino oscillation experiments. Such time-varying masses are assumed to be generated by the coupling between a sterile neutrino and an ultralight scalar field, which in turn affects the light neutrinos by mixing. We demonstrate how various cosmological bounds, such as those coming from big bang nucleosynthesis, the cosmic microwave background, as well as large scale structures, can be evaded in this model. This scenario can be further constrained using multiple terrestrial experiments. In particular, for beta-decay experiments like KATRIN, nontrivial distortions to the electron spectrum can be induced, even when time-variation is fast and it gets averaged. Furthermore, the presence of time-varying masses of sterile neutrinos will alter the interpretation of light sterile neutrino parameter space in the context of the reactor and gallium anomalies. In addition, we also study the impact of such time-varying neutrino masses on results from the BEST collaboration, which have recently strengthened the gallium anomaly. If confirmed, we find that the time-varying neutrino mass hypothesis could give a better fit to the recent BEST data.
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Sanchis-Lozano, M. A. (2022). Stringy Signals from Large-Angle Correlations in the Cosmic Microwave Background? Universe, 8(8), 396–13pp.
Abstract: We interpret the lack of large-angle temperature correlations and the even-odd parity imbalance observed in the cosmic microwave background (CMB) by COBE, WMAP and Planck satellite missions as a possible stringy signal ultimately stemming from a composite inflaton field (e.g., a fermionic condensate). Based on causality arguments and a Fourier analysis of the angular two-point correlation function, two infrared cutoffs k(min)(even,odd) (satisfying k(min)(even) similar or equal to 2k(min)(odd)) are introduced to the CMB power spectrum associated, respectively, with periodic and antiperiodic boundary conditions of the fermionic constituents (echoing the Neveu-Schwarz-Ramond model in superstring theory), without resorting to any particular model.
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Du, M. L., Albaladejo, M., Guo, F. K., & Nieves, J. (2022). Combined analysis of the Z(c)(3900) and the Z(cs)(3985) exotic states. Phys. Rev. D, 105(7), 074018–20pp.
Abstract: We have performed a combined analysis of the BESIII data for both the Z(c)(3900) and Z(cs)(3985) structures, assuming that the latter is an SU(3) flavor partner of the former one. We have improved on the previous analysis of Albaladejo et al. [Phys. Lett. B 755, 337 (2016)] by computing the amplitude for the D-1(D) over barD* triangle diagram considering both D- and S-wave D1D*x couplings. We have also investigated effects from SU(3) light-flavor violations, which are found to be moderate and of the order of 20%. The successful reproduction of the BESIII spectra, in both the hidden-charm and hidden-charm strange sectors, strongly supports that the Z(cs)(3985) and Z(c)(3900) are SU(3) flavor partners placed in the same octet multiplet. The best results are obtained when an energy-dependent term in the diagonal D(*) (D) over bar ((s))((*)) interaction is included, leading to resonances (poles above the thresholds) to describe these exotic states. We have also made predictions for the isovector Z*c and isodoublet Z*(cs), D*(D) over bar*, and D*??D*s molecules, with J(PC) = 1(+-) and J(P) = 1(+), respectively. These states would be heavy-quark spin symmetry (HQSS) partners of the Z(c) and Z(cs). Besides the determination of the masses and widths of the Z(c)(3900) and Z(cs)(3985), we also predict those of the Z*(c) and Z*(cs) resonances.
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Dai, L. R., Oset, E., & Geng, L. S. (2022). The D-s(+)->pi(+KSKS0)-K-0 reaction and the I=1 partner of the f(0)(1710) state. Eur. Phys. J. C, 82(3), 225–9pp.
Abstract: We have identified the decay modes of the D-s(+)-> pi K+*K+*(-),pi+K*(0)(K) over bar*(0) reactions producing a pion and two vector mesons. The posterior vector-vector interaction generates two resonances that we associate to the f(0)(1710) and the a(0)(1710) recently claimed, and they decay to the observed K+K- or (KSKS0)-K-0 pair, leading to the reactions D-s(+)->pi+K+K-,pi(+KSKS0)-K-0. The results depend on two parameters related to external and internal emission. We determine a narrow region of the parameters consistent with the large N-c limit within uncertainties which gives rise to decay widths in agreement with experiment. With this scenario we make predictions for the branching ratio of the a(0)(1710) contribution to the D-s(+)->pi(K+KS0)-K-0 reaction, finding values within the range of (1.3 +/- 0.4)x10(-3). Comparison of these predictions with coming experimental results on that latter reaction will be most useful to deepen our understanding on the nature of these two resonances.
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Dai, L. R., Molina, R., & Oset, E. (2022). The (B)over-bar(0)-> D*+ (D)over-bar*K-0(-) reaction to detect the I=0, J(P)=1+ partner of the X-0(2866). Phys. Lett. B, 832, 137219–5pp.
Abstract: We have chosen the (B) over bar (0)-> D*+ (D) over bar*K-0 reaction in order to observe the I= 0, J(P)= 1(+)(R-1) partner state of the X-0(2866) stemming from the D*+ (K) over bar* molecular picture. The reaction proceeds via external emission in the most favored Cabibbo decay mode and one observes the R(1)state as a very strong peak versus the background in the D*+ K- spectrum. The branching ratio for R1production in this reaction is estimated of the order of 4 x10(-3). The method used, applied to the B+-> D- D+ K+ reaction, produces a ratio of signal to background in the D- K+ spectrum in very good agreement with the LHCb experiment that observed the X-0(2866).
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Fioresi, R., Lledo, M. A., & Razzaq, J. (2022). N=2 quantum chiral superfields and quantum super bundles. J. Phys. A, 55(38), 384012–19pp.
Abstract: We give the superalgebra of N = 2 chiral (and antichiral) quantum superfields realized as a subalgebra of the quantum supergroup SL q (4|2). The multiplication law in the quantum supergroup induces a coaction on the set of chiral superfields. We also realize the quantum deformation of the chiral Minkowski superspace as a quantum principal bundle.
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Boudet, S., Bombacigno, F., Olmo, G. J., & Porfirio, P. (2022). Quasinormal modes of Schwarzschild black holes in projective invariant Chern-Simons modified gravity. J. Cosmol. Astropart. Phys., 05(5), 032–29pp.
Abstract: We generalize the Chern-Simons modified gravity to the metric-affine case and impose projective invariance by supplementing the Pontryagin density with homothetic curvature terms which do not spoil topologicity. The latter is then broken by promoting the coupling of the Chern-Simons term to a (pseudo)-scalar field. The solutions for torsion and nonmetricity are derived perturbatively, showing that they can be iteratively obtained from the background fields. This allows us to describe the dynamics for the metric and the scalar field perturbations in a self-consistent way, and we apply the formalism to the study of quasi normal modes in a Schwarzschild black hole background. Unlike in the metric formulation of this theory, we show that the scalar field is endowed with dynamics even in the absence of its kinetic term in the action. Finally, using numerical methods we compute the quasinormal frequencies and characterize the late-time power law tails for scalar and metric perturbations, comparing the results with the outcomes of the purely metric approach.
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Dai, L. R., Molina, R., & Oset, E. (2022). Prediction of new T-cc states of D* D* and D-s*D* molecular nature. Phys. Rev. D, 105(1), 016029–12pp.
Abstract: We extend the theoretical framework used to describe the T-cc state as a molecular state of D* D and make predictions for the D* D* and D-s(*) D) systems, finding that they lead to bound states only in the J(P) = 1+ channel. Using input needed to describe the T-cc state, basically one parameter to regularize the loops of the Bethe-Salpeter equation, we find bound states with bindings of the order of MeVand similar widths for the D*D* system, while the D*s D-* system develops a strong cusp around the threshold.
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