1,721,002 research outputs found
A Bayesian approach to the constrained MSSM
No full textWe present a new analysis of the Constrained MSSM in terms of Bayesian statistics. We illustrate our results with the light Higgs boson whose inferred mass range one should be able to exclude at the Tevatron with high confidence
Detection prospects of light NMSSM Higgs pseudoscalar via cascades of heavier scalars from vector boson fusion and Higgs-strahlung
No full textA detection at the large hadron collider of a light Higgs pseudoscalar would, if
interpreted in a supersymmetric framework, be a smoking gun signature of nonminimal
supersymmetry. In this work in the framework of the next-to-minimal
supersymmetric standard model we focus on vector boson fusion and Higgs-strahlung
production of heavier scalars that subsequently decay into pairs of light pseudoscalars.
We demonstrate that although these channels have in general very limited reach, they
are viable for the detection of light pseudoscalars in some parts of parameter space and
can serve as an important complementary probe to the dominant gluon-fusion
production mode. We also demonstrate that in a Higgs factory these channels may
reach sensitivities comparable to or even exceeding the gluon fusion channels at the
Large Hadron Collider, thus possibly rendering this our best option to discover a light
pseudoscalar. It is also worth mentioning that for the singlet dominated scalar this may
be the only way to measure its couplings to gauge bosons. Especially promising are
channels where the initial scalar is radiated off a W as these events have relatively high
rates and provide substantial background suppression due to leptons from the W. We
identify three benchmark points that well represent the above scenarios. Assuming that
the masses of the scalars and pseudoscalars are already measured in the gluon-fusion
channel, the event kinematics can be further constrained, hence significantly
improving detection prospects. This is especially important in the Higgs-strahlung
channels with rather heavy scalars, and results in possible detection at 200 fb for the
most favoured parts of the parameter spac
Direct dark matter detection around the corner? Prospects in the Constrained MSSM
Get PDFWe outline the WIMP dark matter parameter space in the Constrained MSSM by performing a comprehensive statistical analysis that compares with experimental data predicted superpartner masses and other collider observables as well as a cold dark matter abundance. We find that 10(-10) pb less than or similar to sigma(SI)(p) less than or similar to 10(-8) pb for direct WIMP detection (with details slightly dependent on the assumptions made). We conclude that most of the 95% probability region for the cross section will be explored by future one-tonne detectors, that will therefore cover most of the currently favoured region of parameter space
A Markov chain Monte Carlo analysis of the CMSSM
Get PDFWe perform a comprehensive exploration of the Constrained MSSM parameter space employing a Markov Chain Monte Carlo technique and a Bayesian analysis. We compute superpartner masses and other collider observables, as well as a cold dark matter abundance, and compare them with experimental data. We include uncertainties arising from theoretical approximations as well as from residual experimental errors of relevant Standard Model parameters. We delineate probability distributions of the CMSSM parameters, the collider and cosmological observables as well as a dark matter direct detection cross section. The 68% probability intervals of the CMSSM parameters are: 0.52TeV < m1/2 < 1.26TeV, m0 < 2.10TeV, −0.34TeV < A0 < 2.41TeV and 38.5 < tan β < 54.6. Generally, large fractions of high probability ranges of the superpartner masses will be probed at the LHC. For example, we find that the probability of mtilde g < 2.7TeV is 78%, of mtilde qR < 2.5TeV is 85% and of mχ1± < 0.8TeV is 65%. As regards the other observables, for example at 68% probability we find 3.5 × 10−9 < BR(Bs→μ+μ−) < 1.7 × 10−8, 1.9 × 10−10 < δaμSUSY < 9.9 × 10−10 and 1 × 10−10 pb < σSIp < 1 × 10−8 pb for direct WIMP detection. We highlight a complementarity between LHC and WIMP dark matter searches in exploring the CMSSM parameter space. We further expose a number of correlations among the observables, in particular between BR(Bs→μ+μ−) and BR(bar B→Xsγ) or σSIp. Once SUSY is discovered, this and other correlations may prove helpful in distinguishing the CMSSM from other supersymmetric models. We investigate the robustness of our results in terms of the assumed ranges of CMSSM parameters and the effect of the (g−2)μ anomaly which shows some tension with the other observables. We find that the results for m0, and the observables which strongly depend on it, are sensitive to our assumptions, while our conclusions for the other variables are robust
Prospects for direct dark matter searches in the constrained mssm
No full textWe outline the WIMP dark matter parameter space in the Constrained MSSM by performing a comprehensive statistical analysis that compares with experimental data predicted superpartner masses and other collider observables as well as a cold dark matter abundance. We find that 10-10pb ≲ σSIp ≲10-8 pb for direct WIMP detection (with details slightly dependent on the assumptions made). We conclude that most of the 95% probability region for the cross section will be explored by future onetonne detectors, that will therefore cover most of the currently favoured region of parameter space
Prospects for direct dark matter detection in the constrained MSSM
Get PDFWe outline the WIMP dark matter parameter space in the constrained MSSM by performing a comprehensive statistical analysis that compares with experimental data predicted superpartner masses and other collider observables as well as a cold dark matter abundance. We include uncertainties arising from theoretical approximations as well as from residual experimental errors on relevant Standard Model parameters.We present high-probability regions for neutralino dark matter direct detection cross section, and we find that 10(-10)pb less than or similar to sigma(SI)(P) less than or similar to ph for direct WIMP detection (with details slightly dependent on the assumptions made). We highlight a complementarity between LHC and WIMP dark matter searches in exploring the CMSSM parameter space. We conclude that most of the 95% probability region for the cross section will be explored by future one-tonne detectors, that will therefore cover most of the currently favoured region of parameter space. (c) 2006 Elsevier B.V. All rights reserved
Implications for the Constrained MSSM from a new prediction for b to s gamma
Get PDFWe re-examine the properties of the Constrained MSSM in light of updated constraints, paying particular attention to the impact of the recent substantial shift in the Standard Model prediction for BR(B to X_s gamma). With the help of a Markov Chain Monte Carlo scanning technique, we vary all relevant parameters simultaneously and derive Bayesian posterior probability maps. We find that the case of \mu>0 remains favored, and that for \mu<0 it is considerably more difficult to find a good global fit to current constraints. In both cases we find a strong preference for a focus point region. This leads to improved prospects for detecting neutralino dark matter in direct searches, while superpartner searches at the LHC become more problematic, especially when \mu<0. In contrast, prospects for exploring the whole mass range of the lightest Higgs boson at the Tevatron and the LHC remain very good, which should, along with dark matter searches, allow one to gain access to the otherwise experimentally challenging focus point region. An alternative measure of the mean quality-of-fit which we also employ implies that present data are not yet constraining enough to draw more definite conclusions. We also comment on the dependence of our results on the choice of priors and on some other assumptions
On the detectability of the CMSSM light Higgs boson at the Tevatron
Get PDFWe examine the prospects of detecting the light Higgs scalar h^0 of the Constrained MSSM at the Tevatron. To this end we explore large ranges of the CMSSM parameter space with mu>0 using a Markov Chain Monte Carlo technique, and apply all relevant collider and cosmological constraints including their uncertainties, as well as those of the Standard Model parameters. Using the formalism of Bayesian statistics we find that the 68% posterior probability region for the light Higgs mass lies between 116.0 GeV and 120.4 GeV. Otherwise, h^0 is very similar to the Standard Model Higgs boson. Nevertheless, we point out some enhancements in its couplings to bottom and tau pairs, ranging from a few per cent in most of the CMSSM parameter space, up to several per cent in the most favored region of tan(beta)~50 and the pseudoscalar Higgs mass of m_A~1 TeV. We also find that the other Higgs bosons are typically too heavy to be produced at the Tevatron. We conclude that, over the whole CMSSM light Higgs 95% posterior probability mass range, a 95% CL exclusion limit can be set with about 2/fb of integrated luminosity per experiment, or else with 4/fb (12/fb) a 3 sigma evidence (5 sigma discovery) will be guaranteed. We also emphasize that the alternative measure of the mean quality of fit favors a somewhat lower Higgs mass range; this implies even more optimistic prospects for the CMSSM light Higgs search than with the more conservative Bayesian approach. In conclusion, at the Tevatron either some evidence will be found for the light Higgs boson or, at a high confidence level, the CMSSM will be ruled out.We examine the prospects of detecting the light Higgs h^0 of the Constrained MSSM at the Tevatron. To this end we explore the CMSSM parameter space with \mu>0, using a Markov Chain Monte Carlo technique, and apply all relevant collider and cosmological constraints including their uncertainties, as well as those of the Standard Model parameters. Taking 50 GeV < m_{1/2}, m_0 < 4 TeV, |A_0| < 7 TeV and 2 < tan(beta) < 62 as flat priors and using the formalism of Bayesian statistics we find that the 68% posterior probability region for the h^0 mass lies between 115.4 GeV and 120.4 GeV. Otherwise, h^0 is very similar to the Standard Model Higgs boson. Nevertheless, we point out some enhancements in its couplings to bottom and tau pairs, ranging from a few per cent in most of the CMSSM parameter space, up to several per cent in the favored region of tan(beta)\sim 50 and the pseudoscalar Higgs mass of m_A\lsim 1 TeV. We also find that the other Higgs bosons are typically heavier, although not necessarily much heavier. For values of the CMSSM light Higgs mass within the 95% probability range as determined by our analysis, a 95% CL exclusion limit can be set with about 2/fb of integrated luminosity per experiment, or else with 4/fb (12/fb) a 3 sigma evidence (5 sigma discovery) will be guaranteed. We also emphasize that the alternative statistical measure of the mean quality-of-fit favors a somewhat lower Higgs mass range: this implies even more optimistic prospects for the CMSSM light Higgs search than the more conservative Bayesian approach. In conclusion, for the above CMSSM parameter ranges, either some evidence will be found at the Tevatron for the light Higgs boson or, at a high confidence level, the CMSSM will be ruled out
On prospects for dark matter indirect detection in the Constrained MSSM
Get PDFIn the framework of the Constrained MSSM we derive the most probable ranges
of the diffuse gamma radiation flux from the direction of the Galactic center
and of the positron flux from the Galactic halo due to neutralino dark matter
annihilation. We find that, for a given halo model, and assuming flat priors,
the 68% probability range of the integrated gamma-ray flux spans about one
order of magnitude, while the 95% probability range can be much larger and
extend over four orders of magnitude (even exceeding five for a tiny region at
small neutralino mass). The detectability of the signal by GLAST depending
primarily on the cuspiness of the halo profile. The positron flux, on the other
hand, appears to be too small to be detectable by PAMELA, unless the boost
factor is at least of order ten and/or the halo profile is extremely cuspy. We
also briefly discuss the sensitivity of our results to the choice of priors
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