Search results for "Potential"
showing 10 items of 3348 documents
Constraints on the Aligned Two-Higgs-Doublet Model and CP violation
2010
The Aligned Two-Higgs-Doublet Model (A2HDM) [Pich A. and Tuzon P. Yukawa Alignment in the Two-Higgs-Doublet Model. Phys. Rev. D80 , (2009), 091702. 0908.1554 ] describes a particular way of enlarging the scalar sector of the Standard Model (SM), with a second Higgs doublet which is aligned to first the one in flavour space. This implies the absence of flavour-changing neutral currents (FCNCs) at tree level and the presence of three complex parameters. Within this general approach, we analyze the charged Higgs phenomenology, including CP asymmetries in the K and B systems [Jung M., Pich A. and Tuzon P. Charged-Higgs phenomenology in the Aligned two-Higgs-doublet model 1006.0470 ].
Global fits in the coloured scalar model
2020
Abstract In this work we study the phenomenological constraints on the parameter space of scalars carrying colour quantum numbers. In particular we constrain the Manohar-Wise model based on the addition of a SU(2) doublet and SU(3) octet to the minimal Higgs model. The fits are performed using the open-source package HEPfit . We include both theoretical constraints, such as unitarity and perturbativity, and experimental constraints, like the ones coming from flavour and electroweak observables. For the first time we combine all these results and we are able to constrain the parameters of the potential, the Yukawa couplings and the masses of the scalars.
The decay η → π0h0 in two-higgs-doublet models
1991
The possibility of a light scalar in the framework of two-Higgs-doublet models is studied. The range of masses 100 MeV < mh0 < 2mπ is already excluded by present experiment bounds on the transition η → π0h0 in the model where the neutral component of one doublet couples to fermions with weak isospin T3 = −12 and the neutral component of the second doublet to fermions with T3 = +12. These bounds also constrain tightly the structure of the Yukawa couplings in two-Higgs-doublet models.
Numerical study of leptogenesis in a 5D split fermion model with bulk neutrinos
2010
We study numerically a 5D hybrid model which incorporates a split fermion scenario and bulk neutrinos. We perform a Monte Carlo analysis of the model in order to find the regions in the parameter space allowing for realization of the leptogenesis. We find that higher order Yukawa terms must be included in order the model to produce a CP violation and net baryon number sufficient for the creation of the observed baryon asymmetry of the Universe.
Low-temperature X-ray detectors for precise Lamb shift measurements on hydrogen-like heavy ions
2000
The precise determination of the Lamb shift in heavy hydrogen-like ions provides a sensitive test of quantum electrodynamics in very strong Coulomb"elds, not accessible otherwise. For the investigation of the Lyman-a transitions in 208Pb81‘ or 238U91‘ with su$cient accuracy a high resolving calorimetric detector for hard X-rays (E)100 keV) is presently developed. The detector modules consist of arrays of silicon thermistors and of X-ray absorbers made of high Z material to optimize the absorption e$ciency. The detectors are housed in a specially designed 3He/4He dilution refrigerator with a side arm which "ts to the geometry of the internal target of the storage ring ESR at GSI Darmstadt. T…
Analytical solution for the solid angle subtended at any point by an ellipse via a point source radiation vector potential
2010
An axially symmetric radiation vector potential is derived for a spherically symmetric point source. This vector potential is used to derive a line integral for the solid angle subtended at a point source by a detector of arbitrary shape and location. An equivalent line integral given previously by Asvestas for optical applications is derived using this formulation. The line integral can be evaluated in closed form for important cases, and the analytical solution for the solid angle subtended by an ellipse at a general point is presented. The solution for the ellipse was obtained by considering sections of a right elliptic cone. The general solution for the ellipse requires the solution of …
Isomer-tagged differential-plunger measurements in proton-unbound 144Ho
2010
The lifetime of an excited state above a weakly populated isomer in the proton-unbound odd-odd nucleus 144Ho has been measured using the recoil distance Doppler shift method. This measurement represents the first differential-plunger lifetime measurement to utilize recoil-isomer tagging. The first excited I[pi]=(10+) state above the two-quasiparticle [pi]h11/2[circle times operator][nu]h11/2(8+) isomer was determined to have a lifetime of [tau]=6(1)�ps. Potential energy surface calculations, based on the configuration-constrained blocking method, predict the isomeric state to have [gamma]-soft triaxial-nuclear shape with [gamma][approximate]24�. The lifetime of the (10+) state can be unders…
Identification of excited states in119Ba
2000
Excited states have been identified in the very neutron-deficient ${}^{119}\mathrm{Ba}$ nucleus. Two bands have been observed, which are likely to be based on ${h}_{11/2}$ and ${(g}_{7/2}{d}_{5/2})$ neutron orbitals. Despite this being the first observation of excited states in ${}^{119}\mathrm{Ba},$ the bands extend to $(75/2)\ensuremath{\Elzxh}$ and $(79/2)\ensuremath{\Elzxh},$ respectively. The bands have been assigned to ${}^{119}\mathrm{Ba}$ using gamma-recoil and gamma--x-ray coincidences. Several quasiparticle alignments have been identified, involving neutron ${(h}_{11/2}{)}^{2}$ and proton ${(h}_{11/2}{)}^{2}$ aligned configurations. Furthermore, the bands show features which are r…
Spectroscopy of nuclei approaching the proton drip-line using a secondary-fragmentation technique with the RISING detector array
2005
An experiment utilizing a double fragmentation reaction was performed to study isobaric analogue states in A similar to 50 nuclei approaching the proton drip-line. gamma-ray spectroscopy will be used to identify excited states in the neutron-deficient nuclei produced in the second fragmentation reaction. Excited state level schemes will be obtained, through comparison with states in their well-known mirror partners, along with information on Coulomb effects through measurements of the Coulomb energy differences between isobaric analogue excited states. The validity of isospin symmetry for nuclei approaching the proton drip-line can also be investigated and the information gained will aid in…
Calculations for a disk source and a general detector using a radiation vector potential
2008
A closed form expression for a radiation vector potential is derived for a generalized disk radiation source. By applying Stokes's theorem the surface integral for the radiation flux into a general detector is converted into a much simpler line integral of the vector potential around the edge of the detector. This line integral can be easily evaluated for general detector geometry and general location and angular orientation relative to the disk source. For a number of cases the line integral reduces to integrals of Bessel functions which give various generalizations of Ruby's formula. Explicit formulas and numerical results for the geometric efficiency are given for circular and elliptical…