Less Minimal Flavour Violation

We consider the approximate U(2)^3 flavour symmetry exhibited by the quark sector of the Standard Model and all its possible breaking terms appearing in the quark Yukawa couplings. Taking an Effective Field Theory point of view, we determine the current bounds on these parameters, assumed to control the breaking of flavour in a generic extension of the Standard Model at a reference scale Lambda. In particular, a significant bound from epsilon'/epsilon is derived, which is relevant to Minimal Flavour Violation as well. In the up-quark sector, the recently observed CP violation in D -> pi+ pi-, K+ K- decays might be accounted for in this generic framework, consistently with any other constraint.Comment: 15 pages, 1 figur

Optical particle counter data collected in two inhabited sites close to an industrial hot spot during a three months survey

Data on this paper describe the monitoring of different size ranges of particulate matter on dwellings positioned close to an integral cycle steel plant. Data were collected by eight channel (PM0.3, PM0.5, PM0.7, PM1, PM2, PM3, PM5, PM10) optical particle counters positioned in two sites. The data were recorded as counts-per-minute for every size channel in a three months survey from June to September 2015. Basic statistical elaboration and boxplot graphs as well as raw data are included

Breaking the electroweak symmetry and supersymmetry by a compact extra dimension

We revisit in some more detail a recent specific proposal for the breaking of the electroweak symmetry and of supersymmetry by a compact extra dimension. Possible mass terms for the Higgs and the matter hypermultiplets are considered and their effects on the spectrum analyzed. Previous conclusions are reinforced and put on firmer ground.Comment: 25 pages, LaTeX, 9 eps figure

Non-perturbative calculation of the two-loop Lamb shift in Li-like ions

A calculation valid to all orders in the nuclear-strength parameter is presented for the two-loop Lamb shift, notably for the two-loop self-energy correction, to the 2p-2s transition energies in heavy Li-like ions. The calculation removes the largest theoretical uncertainty for these transitions and yields the first experimental identification of two-loop QED effects in the region of the strong binding field

Two-Loop Large-mtm_t Electroweak Corrections to K→πννˉK\to\pi\nu\bar\nu for Arbitrary Higgs Boson Mass

We consider for the first time the leading large top mass corrections, arising at higher order in electroweak interactions, to the rare decays $K\to\pi\nu\bar\nu$ and the related modes $B\to X_s\nu\bar\nu$ and $B\to l^+l^-$. Higher order effects of similar type have previously been calculated in the large-$m_t$ limit for key observables of precision electroweak physics at Z-factories. Here we obtain the corresponding corrections of order ${\cal O}(G^2_F m^4_t)$ at the amplitude level for short-distance dominated rare meson decays. This allows us to quantify the importance of higher order electroweak effects for these processes, which can be reliably computed and have very small uncertainties from strong interactions. Simultaneously it becomes possible to remove, to some extent, ambiguities in the definition of electroweak parameters describing the strength of FCNC interactions. The corrections we discuss are at the level of a few percent.Comment: 11 pages, LaTeX, 1 eps-figur

QCD Corrections in two-Higgs-doublet extensions of the Standard Model with Minimal Flavor Violation

We present the QCD corrections to R_b and to the Delta B=1 effective Hamiltonian in models with a second Higgs field that couples to the quarks respecting the criterion of Minimal Flavor Violation, thus belonging either to the (1,2)_1/2 or to the (8,2)_1/2 representation of SU(3)xSU(2)xU(1). After the inclusion of the QCD corrections, the prediction for R_b becomes practically insensitive to the choice of renormalization scheme for the top mass, which for the type-I and type-II models translates in a more robust lower bound on tan(beta). The QCD-corrected determinations of Rb and BR(B->Xs gamma) are used to discuss the constraints on the couplings of a (colored) charged Higgs boson to top and bottom quarks.Comment: 19 pages, 7 figures. v2: version published in Phys. Rev. D, with additional reference and not

Electric Dipole moments of charged leptons and lepton flavor violating interactions in the general two Higgs Doublet model

We calculate the electric dipole moment of electron using the experimental result of muon electric dipole moment and upper limit of the BR(\mu --> e\gamma) in the framework of the general two Higgs doublet model. Our prediction is 10^{-32} e-cm, which lies in the experimental current limits. Further, we obtain constraints for the Yukawa couplings \bar{\xi}^{D}_{N,\tau e} and \bar{\xi}^{D}_{N,\tau\mu}. Finally we present an expression which connects the BR(\tau\to \mu\gamma) and the electric dipole moment of \tau-lepton and study the relation between these physical quantities.Comment: 8 pages, 4 Figures (required epsf sty

Minimal Flavour Violation with hierarchical squark masses

In a supersymmetric model with hierarchical squark masses we analyze a pattern of flavour symmetry breaking centered on the special role of the top Yukawa coupling and, by extension, of the full Yukawa couplings for the up-type quarks. For sufficiently heavy squarks of the first and second generation this leads to effective Minimal Flavour Violation of the Flavour Changing Neutral Current amplitudes. For this to happen we determine the bounds on the masses of the heavy squarks with QCD corrections taken into account, properly including previously neglected effects. We believe that the view presented in this paper altogether strengthens the case for hierarchical sfermions.Comment: 13 pages, 1 figure. v2: an equation correcte

Photoproduction of h_c

Using the NRQCD factorization formalism, we calculate the total cross section for the photoproduction of h_c mesons. We include color-octet and color-singlet mechanisms as well as next-to-leading order perturbative QCD corrections. The theoretical prediction depends on two nonperturbative matrix elements that are not well determined from existing data on charmonium production. For reasonable values of these matrix elements, the cross section is large enough that the h_c may be observable at the E831 experiment and at the HERA experiments.Comment: Revtex file 8 pages, 1 figure. Macros needed: epsf,floats,rotate Minor typos changed, and reference added. Version to be published in Phys.Rev.