Cold Dark Matter and Higgs Mass in the Constrained Minimal Supersymmetric Standard Model With Generalized Yukawa Quasi-Unification

Abstract

The construction of specific supersymmetric grand unified models based on the Pati-Salam gauge group and leading to a set of Yukawa quasi-unification conditions which can allow an acceptable bquark mass within the constrained minimal supersymmetric standard model with µ > 0 is briefly reviewed. Imposing constraints from the cold dark matter abundance in the universe, B physics, and the mass m h of the lighter neutral CP-even Higgs boson, we find that there is an allowed parameter space with, approximately, 44 ≤ tan β ≤ 52, −3 ≤ A 0 /M 1/2 ≤ 0.1, 122 ≤ m h /GeV ≤ 127, and mass of the lightest sparticle in the range (0.75 − 1.43) TeV. Such heavy lightest sparticle masses can become consistent with the cold dark matter requirements on the lightest sparticle relic density thanks to neutralino-stau coannihilations which are enhanced due to stau-antistau coannihilation to down type fermions via a direct-channel exchange of the heavier neutral CP-even Higgs boson. Restrictions on the model parameters by the muon anomalous magnetic moment are also discussed.GUT scale M GUT . In this scheme, we take the electroweak Higgs superfields H 1 , H 2 and the third family right handed quark superfields t c , b c to form SU (2) R doublets. As a result, we obtain 10, 11 the asymptotic Yukawa coupling relation h t = h b and, hence, large tan β ∼ m t /m b . Furthermore, to get h b = h τ and, thus, the asymptotic relation m b = m τ , the third generation quark and lepton SU (2) L doublets [singlets] q 3 and l 3 [b c and τ c ] have to form a SU (4) c 4-plet [4-plet], while the Higgs doublet H 1 which couples to them has to be a SU (4) c singlet. The simplest GUT gauge group which contains both SU (4) c andGiven the experimental values of the top-quark and tau-lepton masses, the CMSSM supplemented by the assumption of YU (which naturally restricts tan β ∼ 50) yields unacceptable values of the b-quark mass for both signs of the MSSM parameter µ. Moreover, the generation of sizable SUSY corrections [17][18][19] to m b (about 20%) drive it well beyond the experimentally allowed region with the µ < 0 case being much less disfavored. Despite this fact, we prefer to focus on the µ > 0 case, since µ < 0 is strongly disfavored by the constraint arising from the deviation δa µ of the measured value of the muon anomalous magnetic moment a µ from its predicted value a SM µ in the standard model (SM). Indeed, µ < 0 is defended 20 only at 3 − σ by the calculation of a SM µ based on the τ -decay data, whereas there is a stronger and stronger tendency 21, 22 at present to prefer the e + e −annihilation data for the calculation of a SM µ , which favor the µ > 0 regime. Note that, the results of Ref. 23,24, where it is claimed that the mismatch between the τ -and e + e − -based calculations is alleviated, disfavor µ < 0 even more strongly.The usual strategy to solve the aforementioned tension between exact YU and fermion masses is the introduction of several kinds of nonuniversalities in the scalar [14][15][16][25][26][27][28][29][30][31] and/or gaugino ...

Probing the hyperbolic branch/focus point region of the constrained minimal supersymmetric standard model with generalized Yukawa quasiunification

“…Comparing the results of Table II with the corresponding ones in theχ −τ 1 coannihilation region -see Table II of Refs. [49,50] -, we may appreciate the different features of the HB/FP solutions presented here. First of all, m 0 acquires considerably larger values here, while µ remains quite small.…”

“…Following our approach in Refs. [49,50], we use as free parameters of the model the ones in Eq. (1).…”

“…[47] and reviewed in Refs. [48,49], which yields a moderate deviation from exact YU and, thus, allows acceptable values of the b-quark mass for both signs of µ within the CMSSM. In particular, the Higgs sector of the simplest PS model [31,32] is extended so that H 2 and H 1 are not exclusively contained in a SU (4) c singlet, SU (2) L × SU (2) R bidoublet superfield, but receive subdominant contributions from another bidoublet too which belongs to the adjoint representation of SU (4) c .…”

“…The parameters α 1 and α 2 describe the mixing of the components of the SU (4) c singlet and 15-plet Higgs bidoublets, while ρ is the ratio of their respective Yukawa coupling constants to the fermions of the third family [49,50]. In our original papers [47,[51][52][53][54], we have considered monoparametric versions of the YQU conditions depending on just one parameter, which was considered for simplicity real and replaced tan β in the investigation of the parametric space of the model.…”

“…In order to overcome this hurdle, we adopted in Refs. [49,50] the more general version of Eq. (2) without imposing any relation between α 1 and α 2 .…”