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.

Abstract: Motivated by a possible interplay between the mechanism of dynamical symmetry breaking and the seesaw mechanism for generating fermion masses, we present a scale-invariant model that extends the gauge symmetry of the Standard Model electroweak sector to SU(3)L (R) U(1)X (R) U(1)N, with a built-in B – L symmetry. The model is based on the symmetry structure of the known 3-3-1 models and, thus, it relates the number of the three observed fermion generations with the cancellation of gauge anomalies. Symmetry breaking is triggered via the Coleman-Weinberg mechanism, taking into account a minimal set of scalar field multiplets. We establish the stability conditions for the tree-level scalar potential imposing the copositivity criteria and use the method of Gildener-Weinberg for computing the one-loop effective potential when one has multiple scalar fields. With the addition of vectorial fermions, getting their mass mainly through the vacuum expectation value of scalar singlets at 103 TeV, the B – L symmetry leads to textures for the fermion mass matrices, allowing seesaw mechanisms for neutrinos and quarks to take place. In particular, these mechanisms could partly explain the mass hierarchies of the quarks. Once the breakdown of the SU(3)L symmetry is supposed to occur around 10 TeV, the model also predicts new particles with TeV-scale masses, such as a neutral scalar H1, a charged scalar HI, and the gauge bosons Z', W'I, and Y0, that could be searched with the high-luminosity LHC.

Abstract: We use a O(alpha(s). Lambda(QCD)/m(c)) heavy quark effective theory scheme, where only O(Lambda(QCD)/mb) corrections are neglected, to study the matrix elements of the scalar, pseudoscalar, vector, axial-vector and tensor currents between the Lambda(b) ground state and the odd parity charm Lambda(c)(2595)(+) and Lambda(c)(2625)(+) resonances. We show that in the near-zero recoil regime, the scheme describes reasonably well, taking into account uncertainties, the results for the 24 form factors obtained in lattice QCD (LQCD) just in terms of only four Isgur-Wise (IW) functions. We also find some support for the possibility that the Lambda(c)(2595)(+) and Lambda(c)(2625)(+) resonances might form a heavy quark spin symmetry (HQSS) doublet. However, we argue that the available LQCD description of these two resonances is not accurate enough to disentangle the possible effects of the Sigma(c)pi and Sigma(c)*pi thresholds, located only a few MeV above their position, and that it cannot be ruled out that these states are not HQSS partners. Finally, we study the ratio d Gamma/[Lambda(b) -> Lambda(c,1/2)-*l (v) over bar (l)]/dq(2)/d Gamma/[Lambda(b) -> Lambda(c,3/2)-*l (v) over bar (l)]/dq(2) of the Standard Model differential semileptonic decay widths, with q the four-momentum transferred between the initial and final hadrons. We provide a natural explanation for the existence of large deviations, near the zero recoil, of this ratio from 1=2 (value predicted in the infinite heavy quark mass limit, assuming that the Lambda(c,1/2)- and Lambda(c,3/2)- are the two members of a HQSS doublet) based on S-wave contributions to the Lambda(b) -> Lambda(c,1/2)- decay amplitude driven by a subleading IW function.

Abstract: A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the Oo10 thorn MeV neutrinos produced by a Galactic core-collapse supernova if one should occur during the lifetime of the experiment. The liquid-argon-based detectors planned for DUNE are expected to be uniquely sensitive to the & nu;e component of the supernova flux, enabling a wide variety of physics and astrophysics measurements. A key requirement for a correct interpretation of these measurements is a good understanding of the energy-dependent total cross section & sigma;oE & nu; thorn for charged-current & nu;e absorption on argon. In the context of a simulated extraction of supernova & nu;e spectral parameters from a toy analysis, we investigate the impact of & sigma;oE & nu; thorn modeling uncertainties on DUNE's supernova neutrino physics sensitivity for the first time. We find that the currently large theoretical uncertainties on & sigma;oE & nu; thorn must be substantially reduced before the & nu;e flux parameters can be extracted reliably; in the absence of external constraints, a measurement of the integrated neutrino luminosity with less than 10% bias with DUNE requires & sigma;oE & nu; thorn to be known to about 5%. The neutrino spectral shape parameters can be known to better than 10% for a 20% uncertainty on the cross-section scale, although they will be sensitive to uncertainties on the shape of & sigma;oE & nu; thorn . A direct measurement of low-energy & nu;e-argon scattering would be invaluable for improving the theoretical precision to the needed level.

Abstract: The nucleon isovector electromagnetic form factors are calculated up to next-to-next-to-leading order by combining relativistic chiral perturbation theory (ChPT) of pion, nucleon, and Delta o1232 thorn with dispersion theory. We specifically address the light-quark mass dependence of the form factors, achieving a good description of recent lattice QCD results over a range of Q2 less than or similar to 0.6 GeV2 and M pi less than or similar to 350 MeV. For the Dirac form factor, the combination of ChPT and dispersion theory outperforms the pure dispersive and pure ChPT descriptions. For the Pauli form factor, the combined calculation leads to results comparable to the purely dispersive ones. The anomalous magnetic moment and the Dirac and Pauli radii are extracted.