Search results for "Bay"
showing 10 items of 1187 documents
A class of invisible axion models with FCNCs at tree level
2014
We build a class of invisible axion models with tree-level Flavor Changing Neutral Currents completely controlled by the fermion mixing matrices. The scalar sector of these models contains three-Higgs doublets and a complex scalar gauge singlet, with the same fermionic content than the Standard Model. A horizontal Peccei-Quinn symmetry provides a solution to the strong CP problem and predicts the existence of a very light and weakly coupled pseudo-Goldstone boson, the invisible axion or familon. A phenomenological analysis is performed taking into account familon searches in rare kaon and muon decays, astrophysical considerations and axion searches via axion-photon conversion. Drastic diffe…
Amplitude analysis ofB0→D¯0K+π−decays
2015
The Dalitz plot distribution of B-0 -> (D) over bar K-0(+)pi(-) decays is studied using a data sample corresponding to 3.0 fb(-1) of pp collision data recorded by the LHCb experiment during 2011 and 2012. The data are described by an amplitude model that contains contributions from intermediate K* (892)(0), K*(1410)(0), K-2*(1430)(0) and D-2(*)(2460)(-) resonances. The model also contains components to describe broad structures, including the K-0(*)(1430)(0) and D-0(*)(2400)(-) resonances, in the K pi S-wave and the D pi S-and P-waves. The masses and widths of the D-0*(2400)(-) and D-2(*)(2460)(-) resonances are measured, as are the complex amplitudes and fit fractions for all components in…
Non-standard antineutrino interactions at Daya Bay
2011
We study the prospects of pinning down the effects of non-standard antineutrino interactions in the source and in the detector at the Daya Bay neutrino facility. It is well known that if the non-standard interactions in the detection process are of the same type as those in the production, their net effect can be subsumed into a mere shift in the measured value of the leptonic mixing angle theta_13. Relaxing this assumption, the ratio of the antineutrino spectra measured by the Daya Bay far and near detectors is distorted in a characteristic way, and good fits based on the standard oscillation hypothesis are no longer viable. We show that, under certain conditions, three years of Daya Bay r…
CKM matrix and fermion masses in the dualized standard model
1997
A Dualized Standard Model recently proposed affords a natural explanation for the existence of Higgs fields and of exactly 3 generations of fermions, while giving at the same time the observed fermion mass hierarchy together with a tree-level CKM matrix equal to the identity matrix. It further suggests a method for generating from loop corrections the lower generation masses and nondiagonal CKM matrix elements. In this paper, the proposed calculation is carried out to 1-loop. It is found first that with the method suggested one can account readily for the masses of the second generation fermions as a `leakage' from the highest generation. Then, with the Yukawa couplings fixed by fitting the…
New Physics and Evidence for a Complex CKM
2005
We carefully analyse the present experimental evidence for a complex CKM matrix, even allowing for New Physics contributions to $\epsilon_{K}$, $a_{J/\Psi K_S}$, $\Delta M_{B_{d}}$, $\Delta M_{B_{s}}$, and the $\Delta I=1/2$ piece of $B\to\rho\rho$ and $B\to\rho\pi$. We emphasize the crucial r\^ ole played by the angle $\gamma$ in both providing irrefutable evidence for a complex CKM matrix and placing constraints on the size of NP contributions. It is shown that even if one allows for New Physics a real CKM matrix is excluded at a 99.92% C.L., and the probability for the phase $\gamma$ to be in the interval $[-170^\circ;-10^\circ]\cup [10^\circ;170^\circ]$ is 99.7%.
Study ofB−→DK−π+π−andB−→Dπ−π+π−decays and determination of the CKM angleγ
2015
We report a study of the suppressed B- -> DK-pi(+)pi(-) and favored B- -> D pi(-)pi(+)pi(-) decays, where the neutral D meson is detected through its decays to the K--/+pi(+/-) and CP -even K+K- and pi(+)pi(-) final states. The measurement is carried out using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb(-1). We observe the first significant signals in the CP - even final states of the D meson for both the suppressed B- -> DK-pi(+)pi(-) and favored B- -> D pi(-)pi(+)pi(-) modes, as well as in the doubly Cabibbo suppressed D -> K+pi(-) final state of the B- -> D pi(-)pi(+)pi(-) decay. Evidence for the suppressed d…
Measurements of |Vcb|, form factors and branching fractions in the decays → ℓ and → ℓ
1997
Two samples of exclusive semileptonic decays, 579 B0 -> D*+l-νl events and 261 B0 -> D+l-νl events, are selected from approximately 3.9 million hadronic Z decays collected by the ALEPH detector at LEP. From the reconstructed differential decay rate of each sample, the product of the hadronic form factor F(ω) at zero recoil of the D(*)+ meson and the CKM matrix element Vcb are measured to be FD*+ (1) Vcb = (31.9 +/- 1.8stat +/- 1.9syst) × 10-3,FD+ (1) Vcb = (27.8 +/- 6.8stat +/- 6.5syst) × 10-3. The ratio of the form factorsFD+ (1) and FD*+ (1) is measured to beFD+ (1)/FD*+ (1) = 0.87 +/- 0.22stat +/- 0.21syst. A value of Vcb is extracted from the two samples, using theoretical constraints o…
Minimal Flavour Violation and Multi-Higgs Models
2010
We propose an extension of the hypothesis of Minimal Flavour Violation (MFV) to general multi-Higgs models without the assumption of Natural Flavour Conservation (NFC) in the Higgs sector. We study in detail under what conditions the neutral Higgs couplings are only functions of V-CKM and propose a MFV expansion for the neutral Higgs couplings to fermions
Flavour constraints on multi-Higgs-doublet models: Yukawa alignment
2010
6 páginas, 3 figuras, 1 tabla.-- Talk given in the "Third Workshop on Theory, Phenomenology and Experiments in Heavy Flavour Physics" (Capri, 5-7 July 2010).
The Proton Spectrum in Neutron Beta Decay: Latest Results with the aSPECT Spectrometer
2009
Abstract The purpose of the neutron decay spectrometer aSPECT is to determine the antineutrino electron angular correlation coefficient a with high precision. Latest measurements with aSPECT were performed during April/May 2008 at the Institut Laue-Langevin in Grenoble, France. In this paper we give a report on the experiment and the status of the ongoing data analysis.