Abstract: Direct searches for lepton flavor violation in decays of the Z boson with the ATLAS detector at the LHC are presented. Decays of the Z boson into an electron or muon and a hadronically decaying r lepton are considered. The searches are based on a data sample of proton-proton collisions collected by the ATLAS detector in 2015 and 2016, corresponding to an integrated luminosity of 36.1 fb(-1) at a center-of-mass energy of root s = 13 TeV. No statistically significant excess of events above the expected background is observed, and upper limits on the branching ratios of lepton-flavor-violating decays are set at the 95% confidence level: B(Z -> e tau) < 5.8 x 10(-5) and B(Z -> μtau) < 2.4 x 10(-5). This is the first limit on B(Z -> e tau) with ATLAS data. The upper limit on 13(Z -> μtau) is combined with a previous ATLAS result based on 20.3 fb(-1) of proton protoncollision data at a center-of-mass energy of root s = 8 TeV and the combined upper limit at 95% confidence level is B(Z -> μtau) < 1.3 x 10(-5).

Abstract: We investigate a simple realistic grand unified theory based on the SU(5) gauge symmetry, which predicts an upper bound on the proton decay lifetime for the channels p -> K+(nu) over bar and p -> pi(+)(nu) over bar, i.e., tau (p -> K+(nu) over bar) less than or similar to 3.4 x 10(35) and tau(p -> pi(+)(nu) over bar) less than or similar to 1.7 x 10(34) years, respectively. In this context, the neutrino masses are generated through the type I and type III seesaw mechanisms, and one predicts that the field responsible for type III seesaw must be light with a mass below 500 TeV. We discuss the testability of this theory at current and future proton decay experiments.

Abstract: We report measurements of sin 2 beta and cos 2 beta using a time-dependent Dalitz plot analysis of B-0 -> D((*))h(0) with D -> K-S(0)pi(+)pi(-) decays, where the light unflavored and neutral hadron h(0) is a pi(0),eta, or omega meson. The analysis uses a combination of the final data sets of the BABAR and Belle experiments containing 471 x 10(6) and 772 x 10(6) B (B) over bar pairs collected at the gamma(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. We measure sin 2 beta = 0.80 +/- 0.14(stat) +/- 0.06(syst) +/- 0.03(model) and cos 2 beta = 0.91 +/- 0.22(stat) +/- 0.09(syst) +/- 0.07(model). The result for the direct measurement of the angle is beta = (22.5 +/- 4.4(stat) +/- 1.2(syst) +/- 0.6(model))degrees. The last quoted uncertainties are due to the composition of the D-0 -> K-S(0)pi(+)pi(-) decay amplitude model, which is newly established by a Dalitz plot amplitude analysis of a high-statistics e(+) e(-) -> c (c) over bar data sample as part of this analysis. We find the first evidence for cos 2 beta > 0 at the level of 3.7 standard deviations. The measurement excludes the trigonometric multifold solution pi/2 – beta = (68.1 +/- 0.7)degrees at the level of 7.3 standard deviations and therefore resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle. The hypothesis of beta = 0 degrees is ruled out at the level of 5.1 standard deviations, and thus CP violation is observed in B-0 -> D-(*) h(0) decays. The measurement assumes no direct CP violation in B-0 -> D-(*) h(0) decays.

Abstract: The full quark-gluon vertex is a crucial ingredient for the dynamical generation of a constituent quark mass from the standard quark gap equation, and its nontransverse part may be determined exactly from the nonlinear Slav nov-Taylor identity that it satisfies. The resulting expression involves not only the quark propagator, but also the ghost dressing function and the quark-ghost kernel, and constitutes the non-abelian extension of the so-called “Ball-Chiu vertex,” known from QED. In the present work we carry out a detailed study of the impact of this vertex on the gap equation and the quark masses generated from it, putting particular emphasis on the contributions directly related with the ghost sector of the theory, and especially the quark-ghost kernel. In particular, we set up and solve the coupled system of six equations that determine the four form factors of the latter kernel and the two typical Dirac structures composing the quark propagator. Due to the incomplete implementation of the multiplicative renormalizability at the level of the gap equation, the correct anomalous dimension of the quark mass is recovered through the inclusion of a certain function, whose ultraviolet behavior is fixed, but its infrared completion is unknown; three particular Ansatze for this function are considered, and their effect on the quark mass and the pion decay constant is explored. The main results of this study indicate that the numerical impact of the quark-ghost kernel is considerable; the transition from a tree-level kernel to the one computed hem leads to a 20% increase in the value of the quark mass at the origin. Particularly interesting is the contribution of the fourth Ball-Chiu form factor, which, contrary to the Abelian case, is nonvanishing, and accounts for 10% of the total constituent quark mass.

Abstract: We study the Upsilon(1S) radiative decays to gamma pi(+)pi(-) and gamma K+K- using data recorded with the BABAR detector operating at the SLAC PEP-11 asymmetric-energy e(+)e(-) collider at center-of-mass energies at the Upsilon(2S) and Upsilon(3S) resonances. The Upsilon(1S) resonance is reconstructed from the decay Upsilon(nS) -> pi(+)pi(-) Upsilon(1S), n =2, 3. Branching fraction measurements and spin-parity analyses of Upsilon(1S) radiative decays are reported for the I = 0 S-wave and f(2) (1270) resonances in the pi(+)pi(-) mass spectrum, the f'(2) (1525) and f(0) (1500) in the K+K mass spectrum, and the f(0)(1710) in both.