1,721,042 research outputs found
On the two-loop sbottom corrections to the neutral Higgs boson masses in the MSSM
No full textWe compute the O(ab*as) two-loop corrections to the neutral Higgs boson masses in the Minimal Supersymmetric Standard Model, using the effective potential approach. Such corrections can be important in the region of parameter space corresponding to tan(beta)>>1 and sizeable mu. In spite of the formal analogy with the O(at*as) corrections, there are important differences, since the dominant effects are controlled by the sbottom-Higgs scalar couplings. We propose a convenient renormalization scheme that avoids unphysically large threshold effects associated with the bottom mass, and absorbs the bulk of the O(ab*as + ab*at) corrections into the one-loop expression. We give general explicit formulae for the O(ab*as) corrections to the neutral Higgs boson mass matrix. We also discuss the importance of the O(ab^2) corrections and derive a formula for their contribution to mh in a simple limiting case
On the neutral Higgs boson masses in the MSSM for arbitrary stop mixing
No full textWe compute the O(alpha (l)alpha (s)) two-loop corrections to the neutral Higgs boson masses in the Minimal Supersymmetric extension of the Standard Model. An appropriate use of the effective potential allows us to obtain simple analytical formulae, valid for arbitrary values of m(A) and of the mass parameters in the stop sector. We elucidate some subtleties of the effective potential calculation, and find full agreement with the numerical output of the existing diagrammatic calculation. We discuss in detail the limit of heavy gluino. (C) 2001 Elsevier Science B.V. All rights reserved
NLO QCD corrections to pseudoscalar Higgs production in the MSSM
No full textWe present a calculation of the two-loop quark-squark-gluino contributions to pseudoscalar Higgs boson production via gluon fusion in the MSSM. We regularize the loop integrals using the Pauli-Villars method, and obtain explicit and compact analytic results based on an expansion in the heavy particle masses. Our results - valid when the pseudoscalar Higgs boson is lighter than squarks and gluinos - can be easily implemented in computer codes for an efficient and accurate determination of the pseudoscalar production cross section
On the two-loop Yukawa corrections to the MSSM Higgs boson masses at large tan(beta)
No full textWe complete the effective potential calculation of the two-loop, top/bottom
Yukawa corrections to the Higgs boson masses in the Minimal Supersymmetric
Standard Model, by computing the O(at^2 + at*ab + ab^2) contributions for
arbitrary values of the bottom Yukawa coupling. We also compute the corrections
to the minimization conditions of the effective potential at the same
perturbative order. Our results extend the existing O(at^2) calculation, and
are relevant in regions of the parameter space corresponding to tan(beta) >> 1.
We extend to the Yukawa corrections a convenient renormalization scheme,
previously proposed for the O(ab*as) corrections, that avoids unphysically
large threshold effects associated with the bottom mass and absorbs the bulk of
the corrections into the one-loop expression. For large values of tan(beta),
the new contributions can account for a variation of several GeV in the
lightest Higgs boson mass
Towards High-Precision Predictions for the MSSM Higgs Sector
Full text linkThe status of the evaluation of the MSSM Higgs sector is reviewed. The
phenomenological impact of recently obtained corrections is discussed. In
particular it is shown that the upper bound on m_h within the MSSM is shifted
upwards. Consequently, lower limits on tan beta obtained by confronting the
upper bound as function of tan beta with the lower bound on m_h from Higgs
searches are significantly weakened. Furthermore, the region in the M_A-tan
beta-plane where the coupling of the lightest Higgs boson to down-type fermions
is suppressed is modified. The presently not calculated higher-order
corrections to the Higgs-boson mass matrix are estimated to shift the mass of
the lightest Higgs boson by up to 3 GeV
On the O(alpha(2)(t)) two-loop corrections to the neutral Higgs boson masses in the MSSM
No full textWe compute the O(alpha(t)(2)) two-loop corrections to the neutral CP-even Higgs boson mass matrix in the Minimal Supersymmetric Standard Model, for arbitrary values of m(A) and of the parameters in the stop sector, in the effective potential approach. In a large region of parameter space these corrections are sizeable, increasing the prediction for m(h), by several GeV. We present explicit analytical formulae for a simplified case. We discuss the inclusion of momentum-dependent corrections and some possible ways of assigning the input parameters. (C) 2002 Elsevier Science B.V. All rights reserved
On the neutral Higgs boson masses in the MSSM for arbitrary stop mixing
No full textWe compute the O(alpha_t alpha_s) two-loop corrections to the neutral Higgs boson masses in the Minimal Supersymmetric extension of the Standard Model. An appropriate use of the effective potential allows us to obtain simple analytical formulae, valid for arbitrary values of mA and of the mass parameters in the stop sector. We elucidate some subtleties of the effective potential calculation, and find full agreement with the numerical output of the existing diagrammatic calculation. We discuss in detail the limit of heavy gluino
Finite quark mass effects in the SM gluon fusion process in POWHEG
No full textThis Report summarises the results of the second year's activities of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. The first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) focuses on predictions (central values and errors) for total Higgs production cross sections and Higgs branching ratios in the Standard Model and its minimal supersymmetric extension, covering also related issues such as Monte Carlo generators, parton distribution functions, and pseudo-observables. This second Report represents the next natural step towards realistic predictions upon providing results on cross sections with benchmark cuts, differential distributions, details of specific decay channels, and further recent development
NLO-QCD corrections to Higgs pair production in the MSSM
Full text linkWe take a step towards a complete NLO-QCD determination of the production of a pair of Higgs scalars in the MSSM. Exploiting a low-energy theorem that connects the Higgs-gluon interactions to the derivatives of the gluon self-energy, we obtain analytic results for the one- and two-loop squark contributions to Higgs pair production in the limit of vanishing external momenta. We find that the two-loop squark contributions can have non-negligible effects in MSSM scenarios with stop masses below the TeV scale. We also show how our results can be adapted to the case of Higgs pair production in the NMSSM
- …
