We compute the exact two-loop matching coefficients for the strong coupling constant alpha_s and the bottom-quark mass m_b within the Minimal Supersymmetric Standard Model (MSSM), taking into account
O(alpha_s^2) contributions from Supersymmetric Quantum Chromodynamics (SQCD). We find that the explicit mass pattern of the supersymmetric particles has a significant impact on the predictions of alpha_s and m_b at high energies. Further on, the three-loop corrections exceed the uncertainty due to the current experimental accuracy. In case of the the running bottom-quark mass, they can reach in the large tan(beta) regime up to 30% of the tree-level value.
Starting with the two-loop effective potential of the MSSM, and assuming a supersymmetric scale well above $M_Z$, we derive a simple analytical approximation for the lightest CP-even Higgs boson mass including resummation of higher order logarithmic terms via RG-improvement and finite non-logarithmic terms up to ${\cal O}(α_sα_t)$. This formula describes the most relevant radiative corrections to the MSSM Higgs boson mass, in particular, those associated with non-zero top-squark mixing.
We evaluate O(alpha_b alpha_s) corrections in the MSSM Higgs boson sector, including an analysis of the renormalization in the bottom/scalar bottom sector. For mu < 0 the genuine two-loop corrections to the mass of the lightest Higgs boson mass can amount up to 3 GeV. Different renormalization schemes are applied and numerically compared. Likewise the residual dependence on the renormalization scale is investigated. This allows to determine the remaining theoretical uncertainties from unknown higher-order corrections at O(alpha_b alpha_s^2) for different regions of the MSSM parameter space.
We evaluate O(alpha_b alpha_s) corrections in the Higgs boson sector of the CP-conserving MSSM, generalising the known result in the literature to arbitrary values of tan beta. A detailed analysis of the renormalisation in the bottom/scalar bottom sector is performed. Concerning the lightest MSSM Higgs boson mass, we find relatively small corrections for positive mu, while for mu < 0 the genuine two-loop O(alpha_b alpha_s) corrections can amount up to 3 GeV. Different renormalisation schemes are applied and numerically compared. It is demonstrated that some care has to be taken in choosing an …
In this paper we compute the $\mathcal{O}(α_s α_t)$ threshold corrections to the running strong coupling constant, the top-Yukawa coupling and the top-quark mass within the MSSM. These parameters present a non-decoupling behaviour with the supersymmetry scale $M_{\rm SUSY}$. Our numerical analysis shows that the mixed QCD-Yukawa corrections can amount to few GeV for the running top-quark mass and range at the percent level for the top-Yukawa coupling.
The paper is devoted to the calculation of the two-loop O(alpha_s y^2) and O(y^4) MSSM corrections to the relation between the pole mass of the b-quark and its running mass in DR scheme. To evaluate the needed diagrams the large mass expansion procedure is used. The obtained contributions are negative in most of the regions of the parameter space and partly compensate the positive O(alpha_s^2) contribution calculated earlier.
We compute the two-loop corrections of O(alpha_s^2) to the Yukawa couplings in the framework of the Minimal Supersymmetric Standard Model (MSSM). The calculation is performed using the effective Lagrangian approach under the approximation of neglecting the Higgs boson mass with respect to the top quark, gluino and all squark flavour masses. As an application we derive the O(alpha_s^2) corrections to the partial decay width of the lightest Higgs boson to a bottom quark pair. We find that the two-loop corrections are sizable for large values of tan_beta and low CP-odd Higgs boson mass. With our …
We compute the top mass dependent NLO strong interaction matching conditions to the Delta F=2 effective Hamiltonian in the general MSSM. We study the relevance of such corrections, comparing its size with that of previously known NLO corrections in the limit mt->0, in scenarios with degeneracy, alignment, and hierarchical squarks. We find that, while these corrections are generally small, there are regions in the parameter space where the contributions to the Wilson coefficients C1 and C4 could partially overcome the expected suppression m_t/M_SUSY.
The evaluation of the two-loop MSSM-contributions to the electroweak precision observables M_W and s_w^eff at order(alpha_t^2), order(alpha_t alpha_b), order(alpha_b^2) is presented. These contributions enter via Delta(rho), and it is explained in detail how one can retain the true, non-vanishing value of the MSSM Higgs boson mass M_h in spite of using the gauge-less limit in the calculation. The numerical results can be sizeable, in particular for strong squark mixing. By comparing the results in the on-shell and DR-bar renormalization schemes, the remaining theoretical uncertainty is found t…
An updated version is presented of the Fortran code FeynHiggs for the evaluation of the neutral CP-even Higgs sector masses and mixing angles. It differs from the previous version by a modification of the renormalization scheme concerning the treatment of subleading terms at the one-loop level; the two-loop corrections, for which the leading contributions of O(alpha_t alphas) and O(alpha_t^2) are implemented, are not affected by the modified renormalization prescription. Besides stabilizing the Higgs mass calculations and avoiding unphysically large threshold effects, the mass of the lightest …
The interpretation of the Higgs signal at \sim 126 GeV within the Minimal Supersymmetric Standard Model (MSSM) depends crucially on the predicted properties of the other Higgs states of the model, as the mass of the charged Higgs boson, MH+-. This mass is calculated in the Feynman-diagrammatic approach within the MSSM with real parameters. The result includes the complete one-loop contributions and the two-loop contributions of O(alpha_t alpha_s). The one-loop contributions lead to sizable shifts in the MH+- prediction, reaching up to \sim 8 GeV for relatively small values of M_A. Even larger …
We compute the two-loop QCD corrections to the neutral Higgs-boson masses in the MSSM, including the effect of non-vanishing external momenta in the self-energies. We obtain corrections of O(alpha_t*alpha_s) and O(alpha*alpha_s), i.e., all two-loop corrections that involve the strong gauge coupling when the only non-vanishing Yukawa coupling is the top one. We adopt either the DRbar renormalization scheme or a mixed OS-DRbar scheme where the top/stop parameters are renormalized on-shell. We compare our results with those of earlier calculations, pointing out an inconsistency in a recent result…
We analyze the minimal supersymmetric Higgs self-couplings at O(alpha_t alpha_s) within the effective potential approach. The two-loop corrections turn out to be of moderate size in the DRbar scheme if the central scale is chosen as half the SUSY scale. The inclusion of the two-loop corrections reduces the renormalization scale dependence to the per-cent level. These results have a significant impact on measurements of the trilinear Higgs self-couplings at the LHC and a future e^+e^- collider.
The Minimal Supersymmetric Extension of the Standard Model (MSSM) features a light Higgs boson, the mass Mh of which is predicted by the theory. Given that the LHC will be able to measure the mass of a light Higgs with great accuracy, a precise theoretical calculation of Mh yields an important test of the MSSM. In order to deliver this precision, we present three-loop radiative corrections of O(alpha_t*alpha_s^2) and provide a computer code that combines our results with corrections to Mh at lower loop orders that are available in the literature.
SUSY meets SMEFT: Complete one-loop matching of the general MSSM
Laboratoire de Physique Subatomique et de Cosmologie, Université Grenoble-Alpes, CNRS/IN2P3（亚原子与宇宙物理学实验室，格勒诺布尔阿尔卑斯大学，法国国家科学研究中心/国家核物理与粒子物理研究所）；Centro de Ciências Naturais e Humanas, Universidade Federal do ABC（自然与人文科学中心，ABC联邦大学）；Departament de Física Teòrica, IFIC (Universitat de València - CSIC)（理论物理系，瓦伦西亚大学-西班牙国家科学研究委员会联合研究所）；Institute for Theoretical Particle Physics and Cosmology, RWTH Aachen University（理论粒子物理学与宇宙学研究所，亚琛工业大学）
The main production mechanism for supersymmetric Higgs particles at hadron colliders crucially depends on the size of their Yukawa couplings to bottom quarks. For sufficiently large tan(beta) the total cross section for some of the neutral Higgs bosons in the MSSM is dominated by bottom-quark fusion. After an introduction to bottom-associated Higgs production, we discuss the complete O(alpha) electroweak and O(alpha_s) strong corrections for the bb-fusion channel in the MSSM. Choosing proper renormalization and input-parameter schemes, an improved Born approximation, constructed from previousl…
When relating the strong coupling $α_s$, measured at the scale of the $Z$ boson mass, to its numerical value at some higher energy, for example the scale of Grand Unification, it is important to include higher order corrections both in the running of $α_s$ and the decoupling of the heavy particles. We compute the two-loop matching coefficients for $α_s$ within the Minimal Supersymmetric Standard Model (MSSM) which are necessary for a consistent three-loop evolution of the strong coupling constant. Different scenarios for the hierarchy of the supersymmetric scales are considered and the numeric…
The leading electroweak MSSM two-loop corrections to the $ρ$-parameter are calculated. They are obtained by evaluating the two-loop self-energies of the Z and the W boson at O(Gf^2 m_t^4) in the limit of heavy scalar quarks. A very compact expression is derived, depending on the ratio of the CP-odd Higgs boson mass, M_A, and the top quark mass, m_t. Expressions for the limiting cases M_A >> m_t and M_A << m_t are also given. The decoupling of the non-SM contribution in the limit M_A -> oo is verified at the two-loop level. The numerical effect of the leading electroweak MSSM two-loop correctio…
A compact approximation formula for the mass of the lightest neutral CP-even Higgs boson, m_h, in the Minimal Supersymmetric Standard Model (MSSM) is derived from the diagrammatic two-loop result for m_h up to O(alpha alpha_s). By analytically expanding the diagrammatic result the leading logarithmic and non-logarithmic as well as the dominant subleading contributions are obtained. The approximation formula is valid for general mixing in the scalar top sector and arbitrary choices of the parameters in the Higgs sector of the model. Its quality is analyzed by comparing it with the full diagramm…
We discuss the automatised calculation of the Higgs mass in renormalisable supersymmetric models with complex parameters at the two-loop level. Our setup is based on the public codes SARAH and SPheno, which can now compute the two-loop corrections to masses of all neutral scalars in such theories. The generic ansatz for these calculations and the handling of the `Goldstone Boson catastrophe' is described. It is shown that we find perfect agreement with other existing two-loop calculations performed in the DR-bar scheme. We also use the functionality to derive results for the MSSM and NMSSM not…
In the Minimal Supersymmetric Standard Model (MSSM) we incorporate the Higgs-boson propagator corrections, evaluated up to two-loop order, into the prediction of $Γ$(h -> ff) and BR(h -> ff) for f = b, c, $τ$. The propagator corrections consist of the full one-loop contribution, including the effects of non-vanishing external momentum, and corrections of O(alpha alpha_s) at the two-loop level. The results are supplemented with the dominant one-loop QED corrections and final state QCD corrections from both gluons and gluinos. The effects of the two-loop propagator corrections and of the one-loo…
We 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 mA 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 mh 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.
Results are presented for the leading two-loop contributions of O(alpha_t alpha_s) to the masses and mixing effects in the Higgs sector of the MSSM with complex parameters. They are obtained in the Feynman-diagrammatic approach using on-shell renormalization. The full dependence on all complex phases is taken into account. The renormalization of the appropriate contributions of the Higgs-boson sector and the scalar top and bottom sector is discussed. Our numerical analysis for the lightest MSSM Higgs-boson mass is based on the new two-loop corrections, supplemented by the full one-loop result.…
FeynHiggsFast is a Fortran code for the calculation of the masses and the mixing angle of the neutral CP-even Higgs bosons in the MSSM up to two-loop order. It is based on a compact analytical approximation formula of the complete diagrammatic one-loop and the dominant two-loop contributions. At the one-loop level a leading logarithmic result is used, taking into account all sectors of the MSSM. At the two-loop level at O(alpha alpha_s) the leading logarithmic and non-logarithmic contributions are taken into account. The approximation formula is valid for arbitrary choices of the parameters in…
CP-violating effects in the Higgs sector of the Minimal Supersymmetric Standard Model with complex parameters (cMSSM) are induced by potentially large higher-order corrections. As a consequence, all three neutral Higgs bosons can mix with each other. Recent results for loop corrections in the Higgs sector of the cMSSM are reviewed. Results for propagator-type corrections of O(alpha_t alpha_s) and complete one-loop results for Higgs cascade decays of the kind h_a -> h_b h_c are summarised, and the proper treatment of external Higgs bosons in Higgs-boson production and decay processes is discuss…
Higgs-boson production in association with bottom quarks is an important discovery channel for supersymmetric Higgs particles at hadron colliders for large values of tan(beta). We present the complete O(alpha) electroweak and O(alpha_s) strong corrections to associated bottom-Higgs production through bb fusion in the MSSM and improve this next-to-leading-order prediction by known two-loop contributions to the Higgs self-energies, as provided by the program FeynHiggs. Choosing proper renormalization and input-parameter schemes, the bulk of the corrections (in particular the leading terms for ta…
Recent calculations of supersymmetric corrections to the conflicting ratios $R_b$ and $R_c$ have shown that an alleged discrepancy between the SM predictions of these observables and the corresponding experimental values can be cured in the MSSM within a certain region of the parameter space. Here we show that, in this very same region, also a well-known discrepancy between the low and high energy determinations of $α_s(M_Z)$ can be disposed of. Specifically, we find that the lineshape determination of the strong coupling constant, which in the SM points towards the large central value $α_s(M_…
Results are presented for the momentum dependent two-loop contributions of O(alpha_t alpha_s) to the masses and mixing effects in the Higgs sector of the MSSM. They are obtained in the Feynman-diagrammatic approach using a mixed on-shell/DRbar renormalization that can directly be matched onto the higher-order corrections included in the code FeynHiggs. The new two-loop diagrams are evaluated with the program SecDec. The combination of the new momentum dependent two-loop contribution with the existing one- and two-loop corrections in the on-shell/DRbar scheme leads to an improved prediction of …
The masses of the neutral CP-even Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM) are predicted on the basis of explicit Feynman-diagrammatic calculations. The results, containing the complete diagrammatic one-loop corrections, the leading two-loop corrections of O(alpha alpha_s) and further improvements taking into account leading electroweak two-loop and higher-order QCD contributions, are discussed and compared with results obtained by renormalization group calculations. Good agreement is found in the case of vanishing mixing in the scalar top sector, while sizable deviatio…
We provide a full one-loop calculation of the self energies and tadpoles of the neutral Higgs bosons of the NMSSM. In addition, we compute the two-loop O(alpha_t*alpha_s+alpha_b*alpha_s) corrections to the neutral Higgs boson masses in the effective potential approximation. With respect to earlier calculations, the newly-computed corrections can account for shifts of a few GeV in the light scalar and pseudoscalar masses, and they can also sizeably affect the mixing between singlet and MSSM-like Higgs scalars. Taking these corrections into account will be crucial for a meaningful comparison bet…
The CMS Collaboration has released the results of its search for supersymmetry, by applying an alphaT method to 1.1/fb of data at 7 TeV. The null result excludes (at 95% CL) a low-mass region of the Constrained MSSM's parameter space that was previously favored by other experiments. Additionally, the negative result of the XENON100 dark matter search has excluded (at 90% CL) values of the spin-independent scattering cross sections sigma^SI_p as low as 10^-8 pb. We incorporate these improved experimental constraints into a global Bayesian fit of the Constrained MSSM by constructing approximate …
We present the calculation of the light neutral CP-even Higgs mass in the MSSM for a heavy SUSY spectrum by resumming enhanced terms through fourth logarithmic order (N$^3$LL), keeping terms of leading order in the top Yukawa coupling $α_t$, and NNLO in the strong coupling $α_s$. To this goal, the three-loop matching coefficient for the quartic Higgs coupling of the SM to the MSSM is derived to order $α_t^2α_s^2$ by comparing the perturbative EFT to the fixed-order expression for the Higgs mass. The new matching coefficient is made available through an updated version of the program Himalaya. …
We calculate the cross sections for the neutral Higgs-boson production at e+e- colliders in the Minimal Supersymmetric Standard Model (MSSM) using the Feynman-diagrammatic approach and the on-shell renormalization scheme. We incorporate the Higgs-boson propagator corrections, evaluated up to two-loop order, into the prediction of the cross sections for the Higgs-boson production mechanism e+e- -> hZ, hA. The propagator corrections consist of the full one-loop contribution, including the effects of non-vanishing external momentum, and at the two-loop level of the dominant corrections of O(alpha…
We 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.
The results of a complete one-loop calculation for the fermionic decay width h^0, H^0, A^0 -> f bar(f) of the neutral MSSM Higgs bosons are presented and the dominant light Higgs decay channel h^0 -> b bar(b) is discussed in detail. The enhancement of the partial decay width h^0 -> b bar(b) compared to the standard Higgs decay is shown for pseudoscalar masses M_A < 300 GeV. Simpler approximation formulae for the Higgs decays are given and their quality is discussed by introducing an effective neutral scalar mixing angle sin(alpha)_eff. Finally the Higgs branching ratios in b bar(b), c bar(c), …
Observing a heavy charged Higgs boson produced in the near future at the Tevatron or at the LHC would be instant evidence of physics beyond the Standard Model. Whether such a Higgs boson would be supersymmetric or not it could only be decided after accurate prediction of its properties. Here we compute the decay width of the dominant decay of such a boson, namely H^+ -> t \bar{b}, including the leading electroweak corrections originating from large Yukawa couplings within the MSSM. These electroweak effects turn out to be of comparable size to the O(alpha_s) QCD corrections in relevant portion…
We compute the order alpha_s^3 (next-to-leading) corrections to the Wilson coefficients of the Delta F=2 effective Hamiltonian in the Minimal Supersymmetric Standard Model with completely arbitrary soft terms. These results are relevant for phenomenological studies of neutral meson mixings in the presence of large squark mass splittings, in particular in hierarchical scenarios of supersymmetry. These corrections achieve a considerable reduction of the uncertainty related to the matching scale ambiguity, and are therefore numerically relevant. We briefly analyze the effect of certain mass split…
We consider the Higgs boson production in the gluon-fusion channel to next-to-next-to-leading order within the Minimal Supersymmetric Standard Model. In particular, we present analytical results for the matching coefficient of the effective theory and study its influence on the total production cross section in the limit where the masses of all MSSM particles coincide. For supersymmetric masses below 500 GeV it is possible to find parameters leading to a significant enhancement of the Standard Model cross section, the $K$-factors, however, change only marginally.
In order to achieve gauge unification at the string scale M_X sim 5.10^17 GeV in the minimal supersymmetric standard model (MSSM) it is necessary to add extra gauge non-singlet representations at an intermediate scale M_I<M_X, leading to a class of models which we refer to as MSSM+X models. We perform a detailed analysis of a large class of MSSM+X models and find that the number of (3,1) representations added must be greater than the total of the number of (3,2) and (1,2) representations. Predictions of M_I, M_X and alpha(M_X) are obtained for models with up to 5 extra vector representations t…
The mass of the lightest CP-even Higgs boson of the minimal supersymmetric extension of the Standard Model (MSSM) has previously been computed including O(alpha alpha_s) two-loop contributions by an on-shell diagrammatic method, while approximate analytic results have also been obtained via renormalization-group-improved effective potential and effective field theory techniques. Initial comparisons of the corresponding two-loop results revealed an apparent discrepancy between terms that depend logarithmically on the supersymmetry-breaking scale, and different dependences of the non-logarithmic…
In multi-Higgs models, the properties of one neutral scalar state approximate those of the Standard Model (SM) Higgs boson in a limit where the corresponding scalar field is roughly aligned in field space with the scalar doublet vacuum expectation value. In a scenario of alignment without decoupling, a SM-like Higgs boson can be accompanied by additional scalar states whose masses are of a similar order of magnitude. In the Minimal Supersymmetric Standard Model (MSSM), alignment without decoupling can be achieved due to an accidental cancellation of tree-level and radiative loop-level effects.…
Low-energy effective field theories (EFT) encode information about the physics at high energies--i.e., the high-energy theory (HET). To extract this information the EFT and the HET have to be matched to each other. At the one-loop level, general results for the matching of renormalizable operators have already been obtained in the literature. In the present paper, we take a step towards a better understanding of renormalizable operator matching at the two-loop level: Focusing on the diagrammatic method, we discuss in detail the various contributions to two-loop matching conditions and compare …
We compute the next-to-leading order strong interaction corrections to gluino-mediated Delta F=2 box diagrams in the Minimal Supersymmetric Standard Model. These corrections are given by two loop diagrams which we have calculated in three different regularization schemes in the mass insertion approximation. We obtain the next-to-leading order Wilson coefficients of the Delta F=2 effective Hamiltonian relevant for neutral meson mixings. We find that the matching scale uncertainty is largely reduced at the next-to-leading order, typically from about 10-15% to few percent.
In this work we push the matching between the QCD operator product expansion (OPE) and resonance chiral theory (RchiT) to order alpha_s. To this end we compute two- and three-point QCD Green functions (GFs) in both theories and compare the results. GFs which are order parameters of chiral symmetry breaking make this matching more transparent and thus we concentrate on those. On the OPE side one needs to calculate the hard-gluon virtual corrections to the quark condensate, and in particular for three-point GFs this computation was hitherto missing. We also discuss the need for including the inf…
Masses of heavy Standard Model fermions (top-quark, bottom-quark, and tau-lepton) play an important role in the analysis of theories beyond the SM. They serve as low-energy input and reduce the parameter space of such theories. In this paper Minimal supersymmetric extension of the SM is considered and two-loop relations between known SM values of fermion masses and running parameters of the MSSM are studied within the effective theory approach. Both b-quark and tau-lepton have the same quantum numbers with respect to SU(2) groupand in the MSSM acquire their masses due to interactions with the …
We present a new global fit to precision electroweak data, including new low- and high-energy data and analyzing the radiative corrections arising from the minimal symmetry breaking sectors of the Standard Model (SM) and its supersymmetric extension (MSSM). It is shown that present data favor a Higgs mass of O(M_Z): M_H = 76+152-50 GeV. We confront our analysis with (meta)stability and perturbative bounds on the SM Higgs mass, and the theoretical upper bound on the MSSM Higgs mass. Present data do not discriminate significantly between the SM and MSSM Higgs mass ranges. We comment in passing o…
In this article we compute the two-loop SQCD corrections to Higgs-quark-quark couplings in the generic MSSM generated by diagrams involving squarks and gluinos. We give analytic results for the two-loop contributions in the limit of vanishing external momenta for general SUSY masses valid in the MSSM with general flavour-structure. Working in the decoupling limit (M_SUSY >> v) we resum all chirally enhanced corrections (related to Higgs-quark-quark couplings) up to order α_s^(n+1) tan(β)^n. This resummation allows for a more precise determination of the Yukawa coupling and CKM elements of the …
For a long time, the minimal supersymmetric standard model (MSSM) with light masses for the supersymmetric states was considered as the most natural extension of the Standard Model of particle physics. Consequently, a valid approximation was to match the MSSM to the precision measurement directly at the electroweak scale. This approach was also utilized by all dedicated spectrum generators for the MSSM. However, the higher the supersymmetric (SUSY) scale is, the bigger the uncertainties which are introduced by this matching. We point out important consequences of a two-scale matching, where th…
We apply the covariant derivative expansion of the Coleman-Weinberg potential to the sfermion sector in the minimal supersymmetric standard model, matching it to the relevant dimension-6 operators in the standard model effective field theory at one-loop level. Emphasis is paid to nondegenerate large soft supersymmetry breaking mass squares, and the most general analytical Wilson coefficients are obtained for all pure bosonic dimension-6 operators. In addition to the non-logarithmic contributions, they generally have another logarithmic contributions. Various numerical results are shown, in par…
In these proceedings we review two aspects of 2HDMs with generic Yukawa structures. The first part considers how recent deviations from the SM expectations in tauonic B decays (observed by BABAR) can be explained in a 2HDM of type III with sizable flavour violation in the up-sector. The second part discusses the matching of the MSSM on the 2HDM of type III. Here we focus on the recently calculated two-loop SQCD corrections to the Higgs-quark-quark couplings.
We consider the QCD corrections to the electric dipole moment of the neutron in the Minimal Supersymmetric Standard Model. We provide a master formula for the Wilson coefficients at the low energy scale including for the first time the mixing between the electric and chromoelectric operators and correcting widely used previous LO estimates. We show that, because of the mixing between the electric and chromoelectric operators, the neutralino contribution is always strongly suppressed. We find that, in general, the effect of the QCD corrections is to reduce the amount of CP violation generated a…
We introduce and explore new heavy Higgs scenarios in the Minimal Supersymmetric Standard Model (MSSM) with explicit CP violation, which have important phenomenological implications that may be testable at the LHC. For soft supersymmetry-breaking scales M_S above a few TeV and a charged Higgs boson mass M_H+ above a few hundred GeV, new physics effects including those from explicit CP violation decouple from the light Higgs boson sector. However, such effects can significantly alter the phenomenology of the heavy Higgs bosons while still being consistent with constraints from low-energy observ…
We compute the O(alpha_s) SUSY-QCD corrections to the W and charged Higgs mediated inclusive semi-tauonic B-decay, B->tau antineutrino_tau X. Combining the SUSY contribution with the SM result obtained from the heavy quark effective field theory, plus ordinary QCD corrections, we find that the allowed region in the (tan(beta),M_H^\pm)-plane could be significantly modified by the short-distance supersymmetric effects. Since the sensitivity to the SUSY parameters other than mu (the higgsino mixing mass) is rather low, the following effective bound emerges for mu<0 at the 2 sigma level: tan(beta)…
In these proceedings we review the flavour phenomenology of two-Higgs-doublet models (2HDMs) and connect the results to the decoupling limit of the MSSM. We first study the impact of FCNC constraints on the allowed parameter space of the 2HDM and examine how recent deviations from the SM expectations in tauonic $B$ decays (observed by BABAR) can be explained in a 2HDM with generic flavour structure (of type III) with sizable flavour violation in the up-sector. Afterwards, we discusses the matching of the MSSM on the 2HDM of type III. Here we focus on the two-loop SQCD corrections to the Higgs-…
We compute the complete two-loop O(alpha) Wilson coefficients relevant for radiative decays of the B meson in the SM. This is a necessary step in the calculation of the O(alpha alpha_s^n ln^n m_b/M_W) corrections and improves on our previous analysis of electroweak effects in B -> X_s gamma. We describe in detail several interesting technical aspects of the calculation and include all dominant QED matrix elements. In our final result, we neglect only terms originated from the unknown O(alpha alpha_s) evolution of the Wilson coefficients and some suppressed two-loop matrix elements. Due to the …
The relation between the quark-gluon description of QCD and the hadronic picture is studied up to order alpha_s. The analysis of the spin-1 correlators is developed within the large NC framework. Both representations are shown to be equivalent in the euclidean domain, where the Operator Product Expansion is valid. By considering different models for the hadronic spectrum at high energies, one is able to recover the alpha_s running in the correlators, to fix the rho(770) and a1(1260) couplings, and to produce a prediction for the values of the condensates. The Operator Product Expansion is impr…
We calculate the Higgs-boson mass spectrum and the corresponding mixing of the Higgs states in the Minimal Supersymmetric Standard Model (MSSM). We assume a mass-hierarchy with heavy SUSY particles and light Higgs bosons. To investigate this scenario, we employ an effective-field-theory approach with a low-energy Two-Higgs-Doublet Model (2HDM) where both Higgs doublets couple to up- as well as down-type fermions. We perform a one-loop matching of the MSSM to the 2HDM and evolve the parameters to the low energy scale by exploiting two-loop renormalization group equations, taking the complex par…
We generalize the analytical expressions for the two-loop leading-log neutral Higgs boson masses and mixing angles to the case of general left- and right-handed soft supersymmetry breaking stop and sbottom masses and left--right mixing mass parameters ($m_Q, m_U, m_D, A_t, A_b$). This generalization is essential for the computation of Higgs masses and couplings in the presence of light stops. At high scales we use the minimal supersymmetric standard model effective potential, while at low scales we consider the two-Higgs doublet model (renormalization group improved) effective potential, with …
Minimal supersymmetric SU(5) GUTs are being squeezed by the recent values of alpha_s, sin^2 theta_W, the lower limit on the lifetime for p to nubar K decay, and other experimental data. We show how the minimal flipped SU(5) GUT survives these perils, accommodating the experimental values of alpha_s and sin^2 theta_W and other constraints, while yielding a p to e/mu+ pi0 lifetime beyond the present experimental limit but potentially accessible to a further round of experiments. We exemplify our analysis using a set of benchmark supersymmetric scenarios proposed recently in a constrained MSSM fr…
We derive the triply differential spectrum for the inclusive rare decay B -> Xs l+ l- in the shape function region, in which Xs is jet-like with $mX^2 \lesssim mb Λ_QCD$. Experimental cuts make this a relevant region. The perturbative and non-perturbative parts of the matrix elements can be defined with the Soft-Collinear Effective Theory, which is used to incorporate alphas corrections consistently. We show that, with a suitable power counting for the dilepton invariant mass, the same universal jet and shape functions appear as in B-> Xs gamma and B-> Xu l nu decays. Parts of the usual alphas…
