Shabbar Raza

Higgs and sparticle spectroscopy with Gauge-Yukawa unification

We explore the Higgs and sparticle spectroscopy of supersymmetric SU(4)c × SU(2)L × SU(2)R models in which the three MSSM gauge couplings and third family (t-b-τ) Yukawa couplings are all unified at MGUT. This class of models can be obtained via compactification of a higher dimensional theory. Allowing for opposite sign gaugino masses and varying mt within 1σ of its current central value yields a variety of gauge-Yukawa unification as well as WMAP compatible neutralino dark matter solutions. They include mixed bino-Higgsino dark matter, stau and gluino coannihilation scenarios, and the A-resonance solution.

t − b − τ Yukawa unification for μ < 0 with a sub-TeV sparticle spectrum

We show compatibility with all known experimental constraints of t − b − τ Yukawa coupling unification in supersymmetric SU(4)c × SU(2)L × SU(2)R which has non-universal gaugino masses and the MSSM parameter μ < 0. In particular, the relic neutralino abundance satisfies the WMAP bounds and Δ(g − 2)μ is in good agreement with the observations. We identify benchmark points for the sparticle spectra which can be tested at the LHC, including those associated with gluino and stau coannihilation channels, mixed bino-Higgsino state and the A-funnel region. We also briefly discuss prospects for testing Yukawa unification with the ongoing and planned direct detection experiments.

Light stop from b–τ Yukawa unification

Abstract We show that b – τ Yukawa unification can be successfully implemented in the constrained minimal supersymmetric model and it yields the stop co-annihilation scenario. The lightest supersymmetric particle is a bino-like dark matter neutralino, which is accompanied by a 10–20% heavier stop of mass ∼ 100 – 330 GeV . We highlight some benchmark points which show a gluino with mass ∼ 0.6 – 1.7 TeV , while the first two family squarks and all sleptons have masses in the multi-TeV range.

Systematic Study of Diphoton Resonance at 750 GeV from Sgoldstino

The ATLAS and CMS Collaborations of the Large Hadron Collider (LHC) have reported an excess of events in diphoton channel with invariant mass of about 750 GeV. With low energy supersymmetry breaking, we systematically consider the sgoldstino scalar S as the new resonance, which is a linear combination of the CP-even scalar s and CP-odd pseudoscalar a. Because we show that s and a can be degenerated or have large mass splitting, we consider two cases for all the following three scenarios: (1) Single resonance, s is the 750 GeV resonance decays to a pair of 1 GeV pseudoscalar a with suitable decay length, these two a decay into collimated pair of photons which cannot be distinguished at the LHC and may appear as diphotons instead of four photons. (2) Twin resonances, ms ≃ ma with a mass difference of about 40 GeV and both s and a decay into diphoton pairs. For productions, we consider three scenarios: (I) vector-boson fusion; (II) gluon–gluon fusion; (III) qq pair production. In all these scenarios with two kinds of resonances, we find the parameter space that satisfies the diphoton production cross-section from 3 to 13 fb and all the other experimental constraints. And we address the decay width as well. In particular, in the third scenario, we observe that the production cross-section is small but the decay width of s or a can be from 40 to 60 GeV. Even if the 750 GeV diphoton excesses were not confirmed by the ATLAS and CMS experiments, we point out that our proposal can be used to explain the current and future diphoton excesses.

NLSP gluino and NLSP stop scenarios from

We present a study of b-tau Yukawa unified supersymmetric SU(4)_c x SU(2)_L x SU(2)_R model (with mu > 0), which predicts the existence of gluino - neutralino and stop - neutralino coannihilation scenarios compatible with the desired relic LSP neutralino dark matter abundance and other collider constraints. The NLSP gluino or NLSP stop masses vary between 400 GeV to ~ 1 TeV. The NLSP gluinos will be accessible at the 14 TeV LHC, while we hope that the NSLP stop solutions will be probed in future LHC searches. We also identify regions of the parameter space in which the gluino and the lighter stop are closely degenerate in mass, interchangeably playing the role of NLSP and NNLSP. We also update a previous study of t-b-tau Yukawa unification and show that NLSP gluino of mass ~ 1 TeV, with a mass difference between the gluino and neutralino of less than 80 GeV, can be realized consistent with the current collider and astrophysical constraints. We present benchmark points for b-tau and t-b-tau Yukawa unification that can be accessible at the LHC.

b-\tau

Considering the Generalized Minimal Supergravity Model (GmSUGRA) in the Minimal Supersymmetric Standard Model (MSSM), we study the Electroweak Supersymmetry (EWSUSY), where the squarks and/or gluino are heavy around a few TeVs while the sleptons, sneutrinos, Bino, Winos, and/or Higgsinos are light within one TeV. We resolves the (g−2)μ/2 discrepancy for the muon anomalous magnetic moment in the Standard Model (SM) successfully and identifies a parameter space where such solutions also have the electroweak fine-tuning measures ∆EW 16.5 (6%) and ∆EW 25 (4%) without and with the WMAP bounds, respectively. We find that the allowed mass ranges, which are consistent within 3σ of the g − 2 discrepancy, for the lightest neutralino, charginos, stau, stau neutrinos, and first two-family sleptons are [44, 390] GeV, [100, 700] GeV, [100, 700], and [52, 700] GeV, respectively. Moreover, our solutions satisfy the latest bounds reported by the ATLAS and CMS Collaborations on electroweakinos and sleptons. The colored sparticles such as light stop, gluinos, and the first two-generation squark masses have been found in the mass ranges of [500, 3000] GeV, [1300, 4300] GeV, and [1800, 4200] GeV, respectively. To obtain the observed dark matter relic density for the Lightest Supersymmetric Particle (LSP) neutralino, we have the bino-wino, LSP neutralino-stau, and LSP neutralino-tau sneutrinos coannihilation scenarios, and the resonance solutions such as A-pole, Higgs-pole, and Z-pole. We identify the higgsino-like LSP neutralino and display its spin-independent and spin-dependent cross sections with nucleons. We present ten benchmark points which can be tested at the up coming collider searches as well. E-mail:tli@itp.ac.cn E-mail:shabbar@itp.ac.cn ar X iv :1 40 9. 39 30 v2 [ he pph ] 2 0 N ov 2 01 4

Yukawa unification

A bstractSupersymmetric grand unified models based on the gauge group SU(5) often require in addition to gauge coupling unification, the unification of b-quark and τ -lepton Yukawa couplings. We examine SU(5) SUSY GUT parameter space under the condition of b − τ Yukawacouplingunificationusing2-loopMSSMRGEsincludingfull1-loopthreshold effects. The Yukawa-unified solutions break down into two classes. Solutions with low tan β ~ 3 − 11 are characterized by

Electroweak supersymmetry from the generalized minimal supergravity model in the MSSM

{m_{{\mathop{g}\limits^{\sim } }}}

Sparticle mass spectra from SU(5) SUSY GUT models with b − τ Yukawa coupling unification

~ 1 − 4 TeV and

A heavier gluino from t–b–τ Yukawa-unified SUSY

{m_{{\mathop{q}\limits^{\sim } }}}