5,841 research outputs found

### A radiatively improved fermiophobic Higgs boson scenario

The naive fermiophobic scenario is unstable under radiative corrections, due
to the chiral-symmetry breaking induced by fermion mass terms. In a recent
study, the problem of including the radiative corrections has been tackled via
an effective field theory approach. The renormalized Yukawa couplings are
assumed to vanish at a high energy scale $\Lambda$, and their values at the
electroweak scale are computed via modified Renormalization Group Equations. We
show that, in case a fermiophobic Higgs scenario shows up at the LHC, a linear
collider program will be needed to accurately measure the radiative Yukawa
structure, and consequently constrain the $\Lambda$ scale.Comment: 7 pages, 3 figures, Proceedings of the 2011 International Workshop on
Future Linear Colliders (LCWS11), Granada (Spain), 26-30 September 201

### Supersymmetric Models and CP violation in B decays

In this talk CP violation in the supersymmetric models, and especially in
B-decays is discussed. We review our analysis of the supersymmetric
contributions to the mixing CP asymmetries of $B\to \phi K_S$ and $B\to
\eta^{\prime} K_S$ processes. Both gluino and chargino exchanges are considered
in a model independent way by using the mass insertion approximation method.
The QCD factorization method is used, and parametrization of this method in
terms of Wilson coefficients is presented in both decay modes. Correlations
between the CP asymmetries of these processes and the direct CP asymmetry in
$b\to s \gamma$ decay are shown.Comment: 16 pages, 7 figures. Prepared for the proceedings of the 1st GUC
workshop on High Energy Physics, Cairo, Jan 9-13, 200

Recommended from our members

### Decision theory and real estate development: a note on uncertainty

Real estate development appraisal is a quantification of future expectations. The appraisal model relies upon the valuer/developer having an understanding of the future in terms of the future marketability of the completed development and the future cost of development. In some cases the developer has some degree of control over the possible variation in the variables, as with the cost of construction through the choice of specification. However, other variables, such as the sale price of the final product, are totally dependent upon the vagaries of the market at the completion date. To try to address the risk of a different outcome to the one expected (modelled) the developer will often carry out a sensitivity analysis on the development. However, traditional sensitivity analysis has generally only looked at the best and worst scenarios and has focused on the anticipated or expected outcomes. This does not take into account uncertainty and the range of outcomes that can happen. A fuller analysis should include examination of the uncertainties in each of the components of the appraisal and account for the appropriate distributions of the variables. Similarly, as many of the variables in the model are not independent, the variables need to be correlated. This requires a standardised approach and we suggest that the use of a generic forecasting software package, in this case Crystal Ball, allows the analyst to work with an existing development appraisal model set up in Excel (or other spreadsheet) and to work with a predetermined set of probability distributions. Without a full knowledge of risk, developers are unable to determine the anticipated level of return that should be sought to compensate for the risk. This model allows the user a better understanding of the possible outcomes for the development. Ultimately the final decision will be made relative to current expectations and current business constraints, but by assessing the upside and downside risks more appropriately, the decision maker should be better placed to make a more informed and “better”

### Looking for anomalous gamma-gamma-H and Z-gamma-H couplings at future linear collider

We consider the possibility of studying anomalous contributions to the
gamma-gamma-H and Z-gamma-H vertices through the process e-gamma--> e-H at
future e-gamma linear colliders, with Sqrt(S)=500-1500 GeV. We make a model
independent analysis based on SU(2)xU(1) invariant effective operators of dim=6
added to the standard model lagrangian. We consider a light Higgs boson (mostly
decaying in bar(b)-b pairs), and include all the relevant backgrounds. Initial
e-beam polarization effects are also analyzed. We find that the process
e-gamma--> e-H provides an excellent opportunity to strongly constrain both the
CP-even and the CP-odd anomalous contributions to the gamma-gamma-H and
Z-gamma-H vertices.Comment: LaTeX, 33 pages, 16 eps figures, extended section

### Experimental Constraints on the Neutralino-Nucleon Cross Section

In the light of recent experimental results for the direct detection of dark
matter, we analyze in the framework of SUGRA the value of the
neutralino-nucleon cross section. We study how this value is modified when the
usual assumptions of universal soft terms and GUT scale are relaxed. In
particular we consider scenarios with non-universal scalar and gaugino masses
and scenarios with intermediate unification scale. We also study superstring
constructions with D-branes, where a combination of the above two scenarios
arises naturally. In the analysis we take into account the most recent
experimental constraints, such as the lower bound on the Higgs mass, the $b\to
s\gamma$ branching ratio, and the muon $g-2$.Comment: References added, bsgamma upper bound improved, results unchanged,
Talk given at Corfu Summer Institute on Elementary Particle Physics, August
31-September 20, 200

### N=1 Supersymmetric Yang-Mills on the lattice at strong coupling

We study N=1 supersymmetric SU(N) Yang-Mills theory on the lattice at strong
coupling. Our method is based on the hopping parameter expansion in terms of
random walks, resummed for any value of the Wilson parameter r in the small
hopping parameter region. Results are given for the mesonic (2-gluino) and
fermionic (3-gluino) propagators and spectrum.Comment: Latex file. 43 pages. Minor additional comments, references added,
typos corrected. Accepted for publication in Int. J. Mod. Phys.

### Chargino contributions to the CP asymmetry in B -> Phi K(S) decay

We perform a model independent analysis of the chargino contributions to the
CP asymmetry in B -> Phi K(S) process. We use the mass insertion approximation
method generalized by including the possibility of a light right-stop. We find
that the dominant effect is given by the contributions of the mass insertions
deltaU_LL(32) and deltaU_RL(32) to the Wilson coefficient of the chromomagnetic
operator. By considering both these contributions simultaneously, the CP
asymmetry in B -> Phi K(S) process is significantly reduced and negative
values, which are within the 1-sigma experimental range and satisfy the b -> s
gamma constraints, can be obtained.Comment: 14 pages, LaTeX, 3.eps Figure

### Implications of effective axial-vector coupling of gluon for $t\bar{t}$ spin polarizations at the LHC

We analyze the impact of effective axial-vector coupling of the gluon on spin
polarization observables in $t\bar{t}$ pair production at the LHC. Working at
leading order in QCD, we compute the $t\bar{t}$ spin-correlation and left-right
spin asymmetry coefficients in the helicity basis in the laboratory frame as
functions of the new physics scale $\Lambda$ associated with this coupling. We
found that the $t\bar{t}$ invariant mass dependent asymmetries are more
sensitive to the scale $\Lambda$ than the corresponding inclusive ones, in
particular when suitable cuts selecting high $t\bar{t}$ invariant mass regions
are imposed. In the context of this scenario, we show that the LHC has
potential either to confirm or to rule out the Tevatron FB top asymmetry
anomaly by analyzing the $t\bar{t}$ spin-correlation and left-right
polarization asymmetries. On the other hand, stringent lower bound on the new
physics scale $\Lambda$ can be set in this scenario if no significant
deviations from the SM predictions for those observables will be measured.Comment: 26 pages, 8 figures, same as published version in PRD. Few
modifications in the text and one new reference adde

### N=1 Super-Yang-Mills on the Lattice: Weak and Strong Coupling Limits

We present a general review about the N=1 supersymmetric SU(Nc) Yang-Mills on the lattice focusing our attention on the quenched approximation in supersymmetry. Finally we analyse and discuss the recent results obtained at strong coupling and large Nc for the mesonic and fermionic propagators and spectrum

### On the B -> X_s l^+ l^- decays in general supersymmetric models

We analyze the inclusive semileptonic decays B -> X_s l^+ l^- in the
framework of the supersymmetric standard model with non-universal soft-breaking
terms at GUT scale. We show that the general trend of universal and
non-universal models is a decreasing of branching ratio (BR) and increasing of
energy asymmetry (AS). However, only non--universal models can have chances to
get very large enhancements in BR and AS, corresponding to large (negative)
SUSY contributions to the b -> s \gamma amplitude.Comment: 13 pages, 3 figures. References added. To appear in Phys. Lett.

- …