Next-to-leading QCD corrections to B → Xsγ in supersymmetry

Ciuchini, M.; Degrassi, Giuseppe; Gambino, Paolo; Giudice, Gian F.

doi:10.1016/s0550-3213(98)00516-1

Cited by 299 publications

(441 citation statements)

References 45 publications

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“…The expressions for the NLO contributions in the two Higgs doublet model has been taken from [22]. The corrections due to supersymmetric particles are calculated under the assumption of minimal flavour violation.…”

Section: Experimental Constraintsmentioning

confidence: 99%

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DarkSUSY: computing supersymmetric dark matter properties numerically

Gondolo

Edsjö

Ullio

et al. 2004

J. Cosmol. Astropart. Phys.

910

1,059

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The question of the nature of the dark matter in the Universe remains one of the most outstanding unsolved problems in basic science. One of the best motivated particle physics candidates is the lightest supersymmetric particle, assumed to be the lightest neutralino -a linear combination of the supersymmetric partners of the photon, the Z boson and neutral scalar Higgs particles. Here we describe DarkSUSY, a publicly-available advanced numerical package for neutralino dark matter calculations. In DarkSUSY one can compute the neutralino density in the Universe today using precision methods which include resonances, pair production thresholds and coannihilations. Masses and mixings of supersymmetric particles can be computed within DarkSUSY or with the help of external programs such as FeynHiggs, ISASUGRA and SUSPECT. Accelerator bounds can be checked to identify viable dark matter candidates. DarkSUSY also computes a large variety of astrophysical signals from neutralino dark matter, such as direct detection in low-background counting experiments and indirect detection through antiprotons, antideuterons, gamma-rays and positrons from the Galactic halo or high-energy neutrinos from the center of the Earth or of the Sun. Here we describe the physics behind the package. A detailed manual will be provided with the computer package.

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Section: Experimental Constraintsmentioning

confidence: 99%

“…The dominant LO contributions which are valid even in the large tan β regime was taken from ref. [23], and we also followed their guideline on how the NLO QCD expressions of [24] should be expanded to the large tan β regime.…”

Section: Experimental Constraintsmentioning

confidence: 99%

DarkSUSY: computing supersymmetric dark matter properties numerically

Gondolo

Edsjö

Ullio

et al. 2004

J. Cosmol. Astropart. Phys.

910

1,059

View full text Add to dashboard Cite

show abstract

“…It is known that the challenge with a charged Higgs in theories is how to escape the constraint from the experimental value of B(B → X s γ) = 2.85 ± 0.41 × 10 −4 [14] which is consistent with that of 3.29 ± 0.33 × 10 −4 predicted in the SM. Following the analysis of [15,16] with the next-to-leading order (NLO) QCD corrections, the lower limit on the charged Higgs mass in the two-Higgs doublet model (model II) is 450 GeV . However, the bound can be released in the framework 1 of supersymmetric theories because of the somewhat cancellation between the particle and its superpartner [17].…”

mentioning

confidence: 99%

“…In Refs. [18] and [19], it has been demonstrated that the NLO contributions in a SUSY model with a sufficient large tanβ may be comparable as that from the leading order (LO). Thus, with choosing a proper sign of the Higgs mass mixing parameter µ, the charged Higgs and chargino contributions to B → X s γ are suppressed.…”

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confidence: 99%

The muon anomalous magnetic moment from a generic charged Higgs with SUSY

Chen

Geng

2001

Physics Letters B

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We study the contribution of a generic charged Higgs (H + ) to the muon anomalous magnetic moment a µ with the SUSY soft breaking parameters. We find out that the deviation between the experimental data and the predicted SM value on a µ can be explained by the two-loop charged Higgs diagrams even with m H + ∼ 400 GeV .It is believed that the muon anomalous magnetic moment, a µ ≡ (g µ −2)/2, would provide precision tests of the standard model (SM) and probe for new physics [1]. Recently, it has been measured at BNL [2] with the data a exp µ = 116 592 023(151) × 10 −11 .(1)The experimental value in Eq. (1) differs from that in the SM [2] despite of the several different theoretical predictions from hadronic contributions [3,4]. In Ref.[2], it was reported that ∆a µ ≡ a exp µ − a SM µ = 426 ± 165 × 10 −11 ,while a recent calculation [4] based on a different estimation from the hadronic part gave ∆a µ = 375 ± 170 × 10 −11 .The values in Eqs. (2) and (3) indicate a window for new physics at 2.6σ and 2.2σ levels, which are translated into 215 × 10 −11 ≤ ∆a µ ≤ 637 × 10 −11 (90% CL) ,andrespectively. It is clear that both ranges in Eqs. (4) and (5) suggest the existence of new physics beyond the SM. However, one must caution about this less than 3σ result until the experiment of E821 at BNL is completed, which should increase the statistical significance at more than 6σ level [5], and the theoretical uncertainties from the hadronic part in a SM µ are further reduced. Recently, various models, such as those with SUSY, scalar bosons, and extra dimensions, which could lead to ∆a µ = O(400 × 10 −11 ) have been explored [1,6,7,8]. In particular, it is discussed extensively to use scalar Higgs bosons in SUSY-like theories as the viable candidates. In Refs. [7,8], the possibilities of using light neutral Higgs bosons with a large tanβ to account ∆a µ at the one-and two-loop levels were studied. It is known that a large tanβ is interesting theoretically since the unification of bottom and tau Yukawa couplings and the explanation of the top to the bottom mass ratio are realized in GUTs if tanβ ∼ O(50) [9]. With this possible large tanβ, it is found that the mass for the scalar boson has to be less than 5 GeV [7] and that for the pseudoscalar 75 GeV with including the Barr-Zee type [10] of the two-loop diagrams [8]. One may conclude that ∆a µ cannot arise from either a scalar or pseudoscalar in the minimal supersymmetric model (MSSM) due to the experimental limits on the scalar and pseudoscalar masses, which are in the ranges of 85 − 95 GeV [11,12,13].In this paper, we would like to examine whether it is possible to use a charged Higgs boson in SUSY models to induce ∆a µ beyond the one loop level. It is known that the challenge with a charged Higgs in theories is how to escape the constraint from the experimental value of B(B → X s γ) = 2.85 ± 0.41 × 10 −4 [14] which is consistent with that of 3.29 ± 0.33 × 10 −4 predicted in the SM. Following the analysis of [15,16] with the next-to-leading order (NLO) QCD corrections, ...

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“…The MFV QCD NLO contributions have been computed for the exchanges of charged Higgs boson and charginos in [15,4,16,17]. In [18], the MFV MSSM NLO QCD contributions have been computed.…”

Section: Introductionmentioning

confidence: 99%

Constraints on supersymmetric flavour models fromb→sγ

Olive

Velasco-Sevilla

2008

J. High Energy Phys.

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We consider the effects of departures from minimal flavour violations (MFV) in the context of CMSSM-like theories. Second and third generation off-diagonal elements in the Yukawa, sfermion, and trilinear mass matrices are taken to be non-zero at the GUT scale.These are run down together with MSSM parameters to the electroweak scale. We apply constraints from fermion masses and CKM matrix elements to limit the range of the new free parameters of the model. We determine the effect of the departure from MFV on the branching ratio of b → s γ. We find that only when the expansion parameter in the down-squark sector is relatively large there is a noticeable effect, which tends to relax the lower limit from b → s γ on the universal gaugino mass. We also find that the expansion parameter associated with the slepton sector needs to be smaller than the corresponding parameter in the down-squark sector in order to be compliant with the bound imposed by the branching ratio of τ → µγ.

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Next-to-leading QCD corrections to B → Xsγ in supersymmetry

Cited by 299 publications

References 45 publications

DarkSUSY: computing supersymmetric dark matter properties numerically

DarkSUSY: computing supersymmetric dark matter properties numerically

The muon anomalous magnetic moment from a generic charged Higgs with SUSY

Constraints on supersymmetric flavour models fromb→sγ

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