LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2018). Central exclusive production of J/psi and (2S) mesons in pp collisions at root s=13 TeV. J. High Energy Phys., 10(10), 167–27pp.
Abstract: Measurements are reported of the central exclusive production of J= and ( 2 S) mesons in pp collisions at a centre- of- mass energy of 13 TeV. Backgrounds are signi fi cantly reduced compared to previous measurements made at lower energies through the use of new forward shower counters. The products of the cross- sections and the branching fractions for the decays to dimuons, where both muons are within the pseudorapidity range 2 : 0 < < 4 : 5, are measured to be The fi rst uncertainties are statistical, the second are systematic, and the third are due to the luminosity determination. The cross- sections are also measured di ff erentially for meson rapidities between 2.0 and 4.5. Good agreement is observed with theoretical predictions. Photoproduction cross- sections are derived and compared to previous experiments, and a deviation from a pure power- law extrapolation of lower energy data is observed.
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Giachino, A., van Hameren, A., & Ziarko, G. (2024). A new subtraction scheme at NLO exploiting the privilege of k<sub>T</sub>-factorization. J. High Energy Phys., 06(6), 167–39pp.
Abstract: We present a subtraction method for the calculation of real-radiation integrals at NLO in hybrid k(T)-factorization. The main difference with existing methods for collinear factorization is that we subtract the momentum recoil, occurring due to the mapping from an (n + 1)-particle phase space to an n-particle phase space, from the initial-state momenta, instead of distributing it over the final-state momenta.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Measurement of CP asymmetries and polarisation fractions in B-s(0) -> K*(0)(K)over-bar*(0) decays. J. High Energy Phys., 07(7), 166–28pp.
Abstract: An angular analysis of the decay B-s(0) -> K*(0)(K) over bar*(0) is performed using pp collisions corresponding to an integrated luminosity of 1.0 fb(-1) collected by the LHCb experiment at a centre-of-mass energy root s = 7TeV. A combined angular and mass analysis separates six helicity amplitudes and allows the measurement of the longitudinal polarisation fraction f(L) = 0.201 +/- 0.057 (stat.) +/- 0.040 (syst.) for the B-s(0) -> K*(892)(0)(K) over bar*(892)(0) decay. A large scalar contribution from the K*(0) (1430) and K*(0) (800) resonances is found, allowing the determination of additional CP asymmetries. Triple product and direct CP asymmetries are determined to be compatible with the Standard Model expectations. The branching fraction B(B-s(0) -> K*(892)(0)(K) over bar*(892)(0)) is measured to be (10.8 +/- 2.1 (stat.) +/- 1.4 (syst.) +/- 0.6 (f(d)/f(s))) x 10(-6).
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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2022). Measurement of prompt charged-particle production in pp collisions at root s=13 TeV. J. High Energy Phys., 01(1), 166–39pp.
Abstract: The differential cross-section of prompt inclusive production of long-lived charged particles in proton-proton collisions is measured using a data sample recorded by the LHCb experiment at a centre-of-mass energy of root s = 13 TeV. The data sample, collected with an unbiased trigger, corresponds to an integrated luminosity of 5.4 nb(-1). The differential cross-section is measured as a function of transverse momentum and pseudorapidity in the ranges P-T is an element of [80, 10 000) MeV/c and eta is an element of [2.0, 4.8) and is determined separately for positively and negatively charged particles. The results are compared with predictions from various hadronic-interaction models.
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Alcaide, J., Salvado, J., & Santamaria, A. (2018). Fitting flavour symmetries: the case of two-zero neutrino mass textures. J. High Energy Phys., 07(7), 164–18pp.
Abstract: We present a numeric method for the analysis of the fermion mass matrices predicted in flavour models. The method does not require any previous algebraic work, it offers a chi(2) comparison test and an easy estimate of confidence intervals. It can also be used to study the stability of the results when the predictions are disturbed by small perturbations. We have applied the method to the case of two-zero neutrino mass textures using the latest available fits on neutrino oscillations, derived the available parameter space for each texture and compared them. Textures A(1) and A(2) seem favoured because they give a small chi(2), allow for large regions in parameter space and give neutrino masses compatible with Cosmology limits. The other “allowed” textures remain allowed although with a very constrained parameter space, which, in some cases, could be in conflict with Cosmology. We have also revisited the “forbidden” textures and studied the stability of the results when the texture zeroes are not exact. Most of the forbidden textures remain forbidden, but textures F-1 and F-3 are particularly sensitive to small perturbations and could become allowed.
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