|
|
Liang, W. H., Oset, E., & Xie, Z. S. (2017). Semileptonic Lambda(b) -> (nu)over-bar(l) l Lambda(c)(2595) and Lambda(b) -> (nu)over-bar(l)l Lambda(c)(2625) decays in the molecular picture of Lambda(c)(2595) and Lambda(c)(2625). Phys. Rev. D, 95(1), 014015–8pp.
Abstract: We evaluate the partial decay widths for the semileptonic Lambda(b) -> (nu) over bar (l) l Lambda(c)(2595) and Lambda(b) -> (nu) over bar (l)l Lambda(c)(2625) decays from the perspective that these two Lambda(c)* resonances are dynamically generated from the DN and D*N interaction with coupled channels. We find that the ratio of the rates obtained for these two reactions is compatible with present experimental data and is very sensitive to the D*N coupling, which becomes essential to obtain agreement with experiment. Together with the results obtained for the Lambda(b) -> pi(-)Lambda(c)* reactions, it gives strong support to the molecular picture of the two Lambda(c)* resonances arid the important role of the DN component neglected in prior studies of the Lambda(c)(2595) from the molecular perspective.
|
|
|
|
Abbas, G. (2017). Low scale left-right-right-left symmetry. Phys. Rev. D, 95(1), 015029–8pp.
Abstract: We propose an effective left-right-right-left model with a parity breaking scale around a few TeV. One of the main achievements of the model is that the mirror fermions as well as the mirror gauge sector simultaneously could be at TeV scale. It is shown that the most dangerous quadratic divergence of the SM Higgs boson involving the top quark in the loop is naturally suppressed, and begins at three loop. The model postpones the fine-tuning of the mass of the SM Higgs boson up to a sufficiently high scale. The model explains the smallness of the neutrino masses whether they are Dirac or Majorana. Furthermore, the strong CP phase is zero in this model.
|
|
|
|
T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Izmaylov, A., Novella, P., Sorel, M., & Stamoulis, P. (2017). First measurement of the muon neutrino charged current single pion production cross section on water with the T2K near detector. Phys. Rev. D, 95(1), 012010–11pp.
Abstract: The T2K off-axis near detector, ND280, is used to make the first differential cross section measurements of muon neutrino charged current single positive pion production on a water target at energies similar to 0.8 GeV. The differential measurements are presented as a function of the muon and pion kinematics, in the restricted phase space defined by p(pi+) > 200 MeV/c, p(mu) > 200 MeV/c, cos(theta(pi+)) > 0.3 and cos(theta(mu)) > 0.3. The total flux integrated nu(mu) charged current single positive pion production cross section on water in the restricted phase space is measured to be <sigma >(phi) = 4.25 +/- 0.48(stat) +/- 1.56(syst) x 10(-40) cm(2)/nucleon. The total cross section is consistent with the NEUT prediction (5.03 x 10(-40) cm(2)/nucleon) and 2 sigma lower than the GENIE prediction (7.68 x 10(-40) cm(2)/nucleon). The differential cross sections are in good agreement with the NEUT generator. The GENIE simulation reproduces well the shapes of the distributions, but overestimates the overall cross section normalization.
|
|
|
|
Kim, C. S., Lopez-Castro, G., Tostado, S. L., & Vicente, A. (2017). Remarks on the Standard Model predictions for R(D) and R(D*). Phys. Rev. D, 95(1), 013003–7pp.
Abstract: Semileptonic b -> c transitions, and in particular the ratios R(D-(*())) = Gamma(B -> D-(*())tau nu)/Gamma(B -> D-(*())l nu), can be used to test the universality of the weak interactions. In light of the recent discrepancies between the experimental measurements of these observables by the BABAR, Belle, and LHCb collaborations and the Standard Model predicted values, we study the robustness of the latter. Our analysis reveals that R(D) might be enhanced by lepton mass effects associated to the mostly unknown scalar form factor. In contrast, the Standard Model prediction for R(D*) is found to be more robust, because possible pollutions from B* contributions turn out to be negligibly small; this indicates that R(D) is a promising observable for searches of new physics.
|
|
|
|
Arbelaez, C., Gonzalez, M., Kovalenko, S. G., & Hirsch, M. (2017). QCD-improved limits from neutrinoless double beta decay. Phys. Rev. D, 96(1), 015010–12pp.
Abstract: We analyze the impact of QCD corrections on limits derived from neutrinoless double beta decay (0 nu beta beta ). As demonstrated previously, the effect of the color mismatch arising from loops with gluons linking the quarks from different color-singlet currents participating in the effective operators has a dramatic impact on the predictions for some particular Wilson coefficients. Here, we consider all possible contributions from heavy particle exchange, i.e. the so-called short-range mechanism of 0 nu beta beta decay. All high-scale models (HSM) in this class match at some scale around a similar to few TeV with the corresponding effective theory, containing a certain set of effective dimension-9 operators. Many of these HSM receive contributions from more than one of the basic operators and we calculate limits on these models using the latest experimental data. We also show with one nontrivial example, how to derive limits on more complicated models, in which many different Feynman diagrams contribute to 0 nu beta beta decay, using our general method.
|
|
|
|
Hati, C., Patra, S., Reig, M., Valle, J. W. F., & Vaquera-Araujo, C. A. (2017). Towards gauge coupling unification in left-right symmetric SU(3)(c) x SU(3)(L) x SU(3)(R) x U(1)(X) theories. Phys. Rev. D, 96(1), 015004–9pp.
Abstract: We consider the possibility of gauge coupling unification within the simplest realizations of the SU(3)(c) x SU(3)(L) x SU(3)(R) xU(1)(X) gauge theory. We present a first exploration of the renormalization group equations governing the “bottom-up” evolution of the gauge couplings in a generic model with free normalization for the generators. Interestingly, we find that for a SU(3)(c) x SU(3)(L) x SU(3)(R) x U(1)(X) symmetry breaking scale M-X as low as a few TeV one can achieve unification in the presence of leptonic octets. We briefly comment on possible grand unified theory frameworks which can embed the SU(3)(c) x SU(3)(L) x SU(3)(R) xU(1)(X) model as well as possible implications, such as lepton flavor violating physics at the LHC.
|
|
|
|
Chatterjee, S. S., Pasquini, P., & Valle, J. W. F. (2017). Resolving the atmospheric octant by an improved measurement of the reactor angle. Phys. Rev. D, 96(1), 011303–6pp.
Abstract: Taking into account the current global information on neutrino oscillation parameters we forecast the capabilities of future long-baseline experiments such as DUNE and T2HK in settling the atmospheric octant puzzle. We find that a good measurement of the reactor angle theta(13) plays a key role in fixing the octant of the atmospheric angle theta(23) with such future accelerator neutrino studies.
|
|
|
|
Chala, M. (2017). Direct bounds on heavy toplike quarks with standard and exotic decays. Phys. Rev. D, 96(1), 015028–14pp.
Abstract: Heavy vectorlike quarks with electric charge Q = 2/3 (also called heavy tops) appear naturally in many extensions of the Standard Model. Although these typically predict the existence of further particles below the TeV scale, direct searches for heavy tops have been performed assuming that they decay only into SM particles. The aim of this paper is to overcome this situation. We consider the most constraining experimental LHC searches for vectorlike quarks, including analyses of the 36 fb(-1) of data collected in the latest run at 13 TeV of center of mass energy, as well as searches sensitive to heavy tops decaying into a new scalar, S. Combining all these, we derive bounds for arbitrary values of the heavy top branching ratios. A simple code that automatizes this process is also provided. At the physics level, we demonstrate that bounds on heavy tops are not inevitably weaker in the presence of new light scalars. We find that heavy tops with masses below similar to 900 GeV are excluded by direct searches, independently of whether they decay into Zt, Ht, Wb or St (with S giving either missing energy of bottom quarks) or into any combination of them.
|
|
|
|
Debastiani, V. R., Dias, J. M., & Oset, E. (2017). Study of the DKK and DK(K)over-bar systems. Phys. Rev. D, 96(1), 016014–9pp.
Abstract: Using the fixed center approximation to Faddeev equations, we investigate the DKK and DK (K) over bar three-body systems, considering that the DK dynamically generates, through its I = 0 component, the D(so)(*()2317) molecule. According to our findings, for the DK (K) over bar interaction we find evidence of a state I(J(p)) = 1/2 (0(-)) just above the D-s0(*)(2317) (K) over bar threshold and around the Df(0)(980) threshold, with mass of about 2833-2858 MeV, made mostly of Df(0)(980). On the other hand, no evidence related to a state from the DKK interaction is found. The state found could be seen in the ppD invariant mass.
|
|
|
|
LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2017). Observation of the B+ -> D*K-(+) pi(+) decay. Phys. Rev. D, 96(1), 011101–10pp.
Abstract: The B+ -> D*K--(+)pi(+) decay potentially provides an excellent way to investigate charm meson spectroscopy. The decay is searched for in a sample of proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb(-1). A clear signal is observed, and the ratio of its branching fraction to that of the B+ -> D*(-)pi(+)pi(+) normalization channel is measured to be beta(B+ -> D*K--(+)pi(+))/beta(B+ -> D*(-)pi(+)pi(+)) = (6.39 +/- 0.27 +/- 0.48) x 10(-2); where the first uncertainty is statistical and the second is systematic. This is the first observation of the B+ -> D*K--(+)pi(+) decay.
|
|
