Della Morte, M., Dooling, S., Heitger, J., Hesse, D., & Simma, H. (2014). Matching of heavy-light flavour currents between HQET at order 1/m and QCD: I. Strategy and tree-level study. J. High Energy Phys., 05(5), 060–31pp.
Abstract: We present a strategy how to match the full set of components of the heavy-light axial and vector currents in Heavy Quark Effective Theory (HQET), up to and including 1/m (h) -corrections, to QCD. While the ultimate goal is to apply these matching conditions non-perturbatively, in this study we first have implemented them at tree-level, in order to find good choices of the matching observables with small contributions. They can later be employed in the non-perturbative matching procedure which is a crucial part of precision HQET computations of semileptonic decay form factors in lattice QCD.
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Baker, M. J., Bordes, J., Hong-Mo, C., & Tsun, T. S. (2011). Mass Hierarchy, Mixing, CP-Violation And Higgs Decay – Or Why Rotation Is Good For Us. Int. J. Mod. Phys. A, 26(13), 2087–2124.
Abstract: The idea of a rank-one rotating mass matrix (R2M2) is reviewed detailing how it leads to ready explanations both for the fermion mass hierarchy and for the distinctive mixing patterns between up and down fermion states, which can be and have been tested against experiment and shown to be fully consistent with existing data. Further, R2M2 is seen to offer, as by-products: (i) a new solution to the strong CP problem in QCD by linking the theta-angle there to the Kobayashi-Maskawa CP-violating phase in the CKM matrix, and (ii) some novel predictions of possible anomalies in Higgs decay observable in principle at the LHC. A special effort is made to answer some questions raised.
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Nieves, J., Feijoo, A., Albaladejo, M., & Du, M. L. (2024). Lowest-lying 1/2- and 3/2- ΛQ resonances: From the strange to the bottom sectors. Prog. Part. Nucl. Phys., 137, 104118–23pp.
Abstract: We present a detailed study of the lowest-lying 1/2(-) and 3/2(-) Lambda Q resonances both in the heavy 2 2 quark (bottom and charm) and the strange sectors. We have paid special attention to the interplay between the constituent quark-model and chiral baryon-meson degrees of freedom, which are coupled using a unitarized scheme consistent with leading-order heavy quark symmetries. We show that the Lambda(b)(5912) [J(P) = 1/2(-)], Lambda(b)(5920) [J(P) = 3/2(-)] and the Lambda(c)(2625) [J(P) = 3/2-], and the Lambda(1520) [J(P) = 3/2(-)] admitting larger breaking corrections, are heavyquark spin-flavor siblings. They can be seen as dressed quark-model states with Sigma Q(()*()) pi molecular components of the order of 30%. The J(P)=1(-) Lambda(2595) has, however, a higher molecular 2 probability of at least 50%, and even values greater than 70% can be easily accommodated. This is because it is located almost on top of the threshold of the Sigma(c)pi pair, which largely influences its properties. Although the light degrees of freedom in this resonance would be coupled to spin-parity 1(-) as in the Lambda(b)(5912), Lambda(b)(5920) and Lambda(c)(2625), the Lambda(c)(2595) should not be considered as a heavy-quark spin-flavor partner of the former ones. We also show that the Lambda(1405) chiral two-pole pattern does not have analogs in the 1 – charmed and bottomed sectors, because the 2 N D-(*()) and N (B) over bar (()*()) channels do not play for heavy quarks the decisive role that the N (K) over bar does in the strange sector, and the notable influence of the bare quark-model states for the charm and bottom resonances. Finally, we predict the existence of two Lambda(b)(6070) and two Lambda(c)(2765) heavy-quark spin and flavor sibling odd parity states.
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Baron, R., Boucaud, P., Dimopoulos, P., Frezzotti, R., Palao, D., Rossi, G., et al. (2010). Light meson physics from maximally twisted mass lattice QCD. J. High Energy Phys., 08(8), 097–41pp.
Abstract: We present a comprehensive investigation of light meson physics using maximally twisted mass fermions for N-f = 2 mass-degenerate quark flavours. By employing four values of the lattice spacing, spatial lattice extents ranging from 2.0 fm to 2.5 fm and pseudo scalar masses in the range 280 less than or similar to m(PS) less than or similar to 650MeV we control the major systematic effects of our calculation. This enables us to confront our N-f = 2 data with SU(2) chiral perturbation theory and extract low energy constants of the effective chiral Lagrangian and derived quantities, such as the light quark mass.
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Ortega, P. G., Entem, D. R., & Fernandez, F. (2017). LHCb pentaquarks in constituent quark models. Phys. Lett. B, 764, 207–211.
Abstract: The recently discovered P-c(4380)(+) and P-c(4450)(+) states at LHCb have masses close to the (D) over bar Sigma(C)* and (D) over bar*Sigma(C) thresholds, respectively, which suggest that they may have significant meson-baryon molecular components. We analyze these states in the framework of a constituent quark model which has been applied to a wide range of hadronic observables, being the model parameters, therefore, completely constrained. The P-c(4380)(+) and P-c(4450)(+) are studied as molecular states composed by charmed baryons and open charm mesons. Several bound states with the proper binding energy are found in the (D) over bar Sigma(C)* and (D) over bar*Sigma(C) chennels. We discuss the possible assignments of these states from their decay widths. Moreover, two more states are predicted, associated with the (D) over bar Sigma(C) and (D) over bar*Sigma*(C) thresholds. (C) 2016 Published by Elsevier B.V.
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Belanger, G., Bharucha, A., Fuks, B., Goudelis, A., Heisig, J., Jueid, A., et al. (2022). Leptoquark manoeuvres in the dark: a simultaneous solution of the dark matter problem and the R-D(*) anomalies. J. High Energy Phys., 02(2), 042–58pp.
Abstract: The measured branching fractions of B-mesons into leptonic final states derived by the LHCb, Belle and BaBar collaborations hint towards the breakdown of lepton flavour universality. In this work we take at face value the so-called R-D(()*()) observables that are defined as the ratios of neutral B-meson charged-current decays into a D-(*())-meson, a charged lepton and a neutrino final state in the tau and light lepton channels. A well-studied and simple solution to this charged current anomaly is to introduce a scalar leptoquark S-1 that couples to the second and third generation of fermions. We investigate how S-1 can also serve as a mediator between the Standard Model and a dark sector. We study this scenario in detail and estimate the constraints arising from collider searches for leptoquarks, collider searches for missing energy signals, direct detection experiments and the dark matter relic abundance. We stress that the production of a pair of leptoquarks that decays into different final states (i.e. the commonly called “mixed” channels) provides critical information for identifying the underlying dynamics, and we exemplify this by studying the t tau b nu and the resonant S-1 plus missing energy channels. We find that direct detection data provides non-negligible constraints on the leptoquark coupling to the dark sector, which in turn affects the relic abundance. We also show that the correct relic abundance can not only arise via standard freeze-out, but also through conversion-driven freeze-out. We illustrate the rich phenomenology of the model with a few selected benchmark points, providing a broad stroke of the interesting connection between lepton flavour universality violation and dark matter.
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Lopez-Ibañez, M. L., Melis, A., Meloni, D., & Vives, O. (2019). Lepton flavor violation and neutrino masses from A(5) and CP in the non-universal MSSM. J. High Energy Phys., 06(6), 047–34pp.
Abstract: We analyze the phenomenological consequences of embedding a flavor symmetry based on the groups A(5) and CP in a supersymmetric framework. We concentrate on the leptonic sector, where two different residual symmetries are assumed to be conserved at leading order for charged and neutral leptons. All possible realizations to generate neutrino masses at tree level are investigated. Sizable flavor violating effects in the charged lepton sector are unavoidable due to the non-universality of soft-breaking terms determined by the symmetry. We derive testable predictions for the neutrino spectrum, lepton mixing and flavor changing processes with non-trivial relations among observables.
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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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Bartl, A., Eberl, H., Herrmann, B., Hidaka, K., Majerotto, W., & Porod, W. (2011). Impact of squark generation mixing on the search for squarks decaying into fermions at LHC. Phys. Lett. B, 698(5), 380–388.
Abstract: We study the effect of squark generation mixing on squark production and decays at LHC in the Minimal Supersymmetric Standard Model (MSSM). We show that the effect can be very large despite the very strong constraints on quark-flavour violation (QFV) from experimental data on B mesons. We find that the two lightest up-type squarks (u) over bar (1.2) can have large branching ratios for the decays into c (chi) over bar (0)(1) and t (chi) over bar (0)(1) at the same time due to squark generation mixing, leading to QFV signals 'pp -> c (t) over bar (t (c) over bar) + missing-E-T + X' with a significant rate. The observation of this remarkable signature would provide a powerful test of supersymmetric QFV at LHC. This could have a significant impact on the search for squarks and the determination of the underlying MSSM parameters.
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Albaladejo, M., Daub, J. T., Hanhart, C., Kubis, B., & Moussallamd, B. (2017). How to employ (B)over-bar(d)(0) -> J/psi(pi eta, (K)over-barK) decays to extract information on pi eta scattering. J. High Energy Phys., 04(4), 010–28pp.
Abstract: We demonstrate that dispersion theory allows one to deduce crucial information on pi eta scattering from the final-state interactions of the light mesons visible in the spectral distributions of the decays (B) over bar (0)(d) -> J/psi(pi(0)eta, K+K-, K-0 (K) over bar (0)). Thus high-quality measurements of these differential observables are highly desired. The corresponding rates are predicted to be of the same order of magnitude as those for (B) over bar (0)(d) -> J/psi pi(+)pi(-) measured recently at LHCb, letting the corresponding measurement appear feasible.
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