Muon g−2 in an alternative quasi-Yukawa unification with a less fine-tuned seesaw mechanism

Abstract

We explore the low-scale implications of the Pati-Salam Model including the TeV scale right-handed neutrinos interacting and mixing with the MSSM fields through the inverse seesaw (IS) mechanism in light of the muon anomalous magnetic moment (muon g − 2) resolution and highlight the solutions which are compatible with the quasi-Yukawa unification condition (QYU). We find that the presence of the righthanded neutrinos causes heavy smuons as mμ ≳ 800 GeV in order to avoid tachyonic staus at the low scale. On the other hand, the sneutrinos can be as light as about 100 GeV, and along with the light charginos of mass ≲400 GeV, they can yield such large contributions to muon g − 2 that the discrepancy between the experiment and the theory can be resolved. These solutions also require m˜χAE We also discuss such light chargino and neutralino along with the light stau (mτ ≳ 200 GeV) in the light of current LHC results. Besides, the gluino mass lies in a range ∼½2.5-3.5 TeV, which is tested in near future experiments. In addition, the model predicts relatively light Higgsinos (μ ≲ 700 GeV); hence, the second chargino mass is also light enough (≲700 GeV) to contribute to muon g − 2. Light Higgsinos also yield less fine-tuning at the electroweak scale, and the regions compatible with muon g − 2 restrict Δ EW ≲ 100 strictly, and this region also satisfies the QYU condition. In addition, the ratios among the Yukawa couplings should be 1.8 ≲ y t /y b ≲ 2.6, y τ /y b ∼ 1.3 to yield correct fermion masses. Even though the righthanded neutrino Yukawa coupling can be varied freely, the solutions bound its range to 0.8 ≲ y ν /y b ≲ 1.7.

Sparticle spectroscopy and dark matter in a U(1)B−L extension of MSSM

“…However, if the model is constrained by the gauge coupling unification condition (g 1 = g 2 = g B−L ) at M GUT , the renormalization group evolution leads to g B−L g 2 at the weak scale (see, for instance, eq. (3.1) in [4][5][6][7][8][9][10][11][12][13]). This result may slightly strengthen the signal process, but it is still beyond the reach of the current LHC experiments, since the stop mass is bounded at about 3 TeV from below by the Planck bound in our model.…”

“…the relic density of the LSP neutralino (red) shrinks this range to [4,10] TeV. When the 300 fb −1 integrated luminosity is collected in the collider experiments with 14 TeV center of mass energy, the squarks can be probed up to 2.7 TeV, while this scale is expected to raise to about 3 TeV when the integrated luminosity reaches to 3000 fb −1 [76].…”

“…The spontaneous breaking of U(1) B−L with a Higgs field carrying two units of B − L charge leaves unbroken a Z 2 symmetry which is precisely 'matter' parity. This Z 2 symmetry coincides with the subgroup of Z 4 , the center of SO(10) (more precisely Spin (10)), and it is realized as an unbroken symmetry if the SO (10) breaking is achieved with fields in the tensor representations [3]. The presence of this unbroken Z 2 symmetry ensures that the lightest supersymmetric particle (LSP) is stable and if neutral, it is a viable dark matter candidate.…”

“…Motivated by the planned Run-3 at the LHC next year, we explore the low energy consequences of MSSM supplemented by U(1) B−L as well as a U(1) R symmetry. A low scale breaking of U(1) B−L symmetry in SUSY models yields a rich phenomenology [4][5][6][7][8][9][10][11][12][13]. There appears a Z gauge boson together with its SUSY fermion partnerB .…”

“…× 10 −10 3.23 × 10 −10 2.4 × 10 −10 3.85 × 10 −10 2.6 × 10 −11 σ SD (pb) 1.92 × 10 −7 3.60 × 10 −7 2.075 × 10 −7 2.39 × 10 −8 1.11 × 10 −7 Masses are in units of GeV, µ > 0 and all points satisfy the sparticle mass bounds, and B-physics constraints described in section 3. Points 1 and 2 represent chargino-neutralino coannihilation and stau NLSP respectively.…”