We study the naturalness properties of the B − L Supersymmetric Standard Model (BLSSM) with Type-I seesaw and compare them to those of the Minimal Supersymmetric Standard Model (MSSM) at both low (i.e., Large Hadron Collider) energies and high (i.e., unification) scales. By adopting standard measures of naturalness, we assess that, in presence of full unification of the additional gauge couplings and scalar/fermionic masses of the BLSSM, such a scenario reveals a somewhat higher degree of Fine-Tuning (FT) than the MSSM, when the latter is computed at the unification scale and all available theoretical and experimental constraints, but the Dark Matter (DM) ones, are taken into account. Yet, such a difference, driven primarily by the collider limits requiring a high mass for the gauge boson associated to the breaking of the additional U (1) B−L gauge group of the BLSSM in addition to the SU (3) C × SU (2) L × U (1) Y of the MSSM, should be regarded as a modest price to pay for the former in relation to the latter, if one notices that the non-minimal scenario offers a significant volume of parameter space where numerous DM solutions of different compositions can be found to the relic density constraints, unlike the case of the minimal structure, wherein only one type of solution is accessible over an ever diminishing parameter space. In fact, this different level of tension within the two SUSY models in complying with current data is well revealed when the FT measure is recomputed in terms of the low energy spectra of the two models, over their allowed regions of parameter space now in presence of all DM bounds, as it is shown that the tendency is now opposite, the BLSSM appearing more natural than the MSSM. Contents 1 Introduction 1 2 The B − L Supersymmetric Standard Model 3 3 Renormalisation Group Equations 7 4 Collider and Dark Matter Constraints 10 5 Fine-Tuning Measures 13 6 Results 15

We employ the Yukawa coupling unification condition, y t = y b = y τ at M GUT , inspired by supersymmetric SO(10) models, to estimate the lightest Higgs boson mass as well as masses of the associated squarks and gluino. We employ non-universal soft masses, dictated by SO(10) symmetry, for the gauginos. Furthermore, the soft masses for the two scalar Higgs doublets are set equal at M GUT , and in some examples these are equal to the soft masses for scalars in the matter multiplets. For µ > 0, M 2 > 0, where M 2 denotes the SU (2) gaugino mass, essentially perfect t-b-τ Yukawa unification is possible, and it predicts a Higgs mass of 122 -124 GeV with a theoretical uncertainty of about ±3 GeV. The corresponding gluino and the first two family squarks have masses 3 TeV. We present some LHC testable benchmark points which also show the presence of neutralino-stau coannihilation in this scenario. The well-known MSSM parameter tan β ≈ 47.

We consider two classes of supersymmetric models with nonuniversal gaugino masses at M GUT in an attempt to resolve the apparent muon g − 2 anomaly encountered in the Standard Model. We explore two distinct scenarios, one in which all gaugino masses have the same sign at M GUT , and a second case with opposite sign gaugino masses. The sfermion masses in both cases are assumed to be universal at M GUT . We exploit the non universality among gaugino masses to realize large mass splitting between the colored and non-colored sfermions. Thus, the sleptons can have masses in the few hundred GeV range, whereas the colored sparticles turn out to be an order of magnitude or so heavier. In both models the resolution of the muon g − 2 anomaly is compatible, among other things, with a 125 − 126 GeV Higgs boson mass and the WMAP dark matter bounds.

In this paper, we examine the consistency of the Large Hadron Collider (LHC) data collected during Runs 1 and 2 by the ATLAS and CMS experiments with the predictions of a 2-Higgs doublet model embedding vectorlike quarks (VLQs) for pp → H, A production and H, A → γγ decay mechanisms, respectively, of (nearly) degenerate CP-even (H) and CP-odd (A) Higgs bosons. We show that a scenario containing one single VLQ with electromagnetic charge 2=3 can explain the above ATLAS and CMS data for masses in the region 350 GeV ≤ m VLQ ≤ 1.5 TeV or so, depending on tan β, and for several values of the mixing angle between the top quark (t) and its VLQ counterpart (T). We then perform a global fit onto the model by including all relevant experimental as well as theoretical constraints. The surviving samples of our analysis are discussed within 2σ of the LHC measurements. Additionally, we also comment on the recent anomalous result reported by CMS using Run 2 data on the associated Standard Model Higgs boson production with top quark pairs pp → tth with an observed significance of 3.3σ. Other than these specific examples, we also present a phenomenological analysis of the main features of the model, including the most promising T decay channels.

We revisit a class of supersymmetric SO(10) models with t-b-τ Yukawa coupling unification condition, with emphasis on the prediction of the Higgs mass. We discuss qualitative features in this model that lead to a Higgs mass prediction close to 125 GeV. We show this with two distinct computing packages, Isajet and SuSpect, and also show that they yield similar global features in the parameter space of this model. We find that t-b-τ Yukawa coupling unification prefers values of the CP-odd Higgs mass m A to be around 600 GeV, with all colored sparticle masses above 3 TeV. We also briefly discuss prospects for testing this scenario with the ongoing and planned direct dark matter detection experiments. In this class of models with t-b-τ Yukawa unification, the neutralino dark matter particle is heavy (mχ0 1 400 GeV), which coannihilates with a stau to yield the correct relic abundance.

We present a study of b-τ Yukawa unified supersymmetric SU (4) c × SU (2) L × SU (2) R model (with µ > 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 − τ 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−τ and t−b−τ Yukawa unification that can be accessible at the LHC.

In this work we study implications of additional non-holomorphic soft breaking terms (µ , A t , A b and A τ ) on the MSSM phenomenology. By respecting the existing bounds on the mass measurements and restrictions coming from certain B-decays, we probe reactions of the MSSM to these additional soft breaking terms. We provide examples in which some slightly excluded solutions of the MSSM can be made to be consistent with the current experimental results. During this, even after applying additional fine-tuning constraints the non-holomorphic terms are allowed to be as large as hundreds of GeV. Such terms prove that they are capable of enriching the phenomenology and varying the mass spectra of the MSSM heavily, with a reasonable amount of fine-tuning.We observe that higgsinos, the lightest stop, the heavy Higgs boson states A, H, H ± , sbottom and stau exhibit the highest sensitivity to the new terms. We also show how the light stop can become nearly degenerate with top quark using these nonholomorphic terms.

Motivated by the tension between the Higgs mass and muon g − 2 in minimal supersymmetric standard model (MSSM), we analyze the muon g − 2 in supersymmertic B − L extension of the standard model (BLSSM) with inverse seesaw mechanism. In this model, the Higgs mass receives extra important radiative corrections proportional to large neutrino Yukawa coupling. We point out that muon g − 2 also gets significant contribution, due to the constructive interferences of light neutralino effects. The light neutralinos are typically the MSSM Bino like and the supersymmetric partner of U (1)B−L gauge boson (B ino). We show that with universal soft supersymmetry breaking terms, the muon g − 2 resides within 2σ of the measured value, namely ∼ 17 × 10 −10 , with Higgs mass equal to 125 GeV . PACS numbers:The Standard Model (SM) prediction for the anomalous magnetic moment of the muon, a µ = (g − 2) µ /2 (hereafter muon g − 2) has a discrepancy with the experimental results:This discrepancy has survived after performing highly accurate theoretical calculations [1] within the SM framework and experimental analyses [2]; and hence, it can be resolved or ameliorated by contributions from new physics beyond the SM (BSM). If supersymmetry (SUSY), as one of the forefront candidates for the BSM physics, is a solution to the muon g − 2, the SUSY particles, namely, smuon and weak gaugino (Bino or Wino) masses should be around a few hundred GeV, in order to utilize the supersymmetric contributions [3]. However, the observation of the Higgs boson of mass about 125 GeV requires rather heavy sparticle spectrum within the MSSM framework, and it results in a strong tension in simultaneous resolution for both the 125 GeV Higgs boson and the muon g−2 problem since SUSY contributions to muon g − 2 is suppressed by the heavy spectrum. Non-universality in gaugino and/or scalar masses may remove this tension [4], nevertheless in this case SUSY models will have plenty of free parameters and will lose their productivity.In this article we show that this tension can be alleviated in the U (1) B−L extended Supersymmetric Standard Model (BLSSM), which is one of the interesting nonminimal realizations of supersymmetry. The BLSSM is also well motivated by the established existence of nonzero neutrino masses [5]. It turns out that, in this class of model, the scale of B − L symmetry breaking can be related to the scale of SUSY breaking [6], therefore, a TeV scale type I or inverse seesaw mechanism can be naturally implemented [7]. The one-loop radiative corrections to the SM-like Higgs boson mass, due to the right-handed (s)neutrinos in BLSSM, with inverse seesaw mechanism, provide new contribution to the Higgs boson mass in addition to the stop sector of MSSM [8]. Thus the lower bound imposed by Higgs mass on the uni-versal gaugino soft masses m 1/2 is reduced, which makes possible to find solutions with the light weak gauginos. Moreover, in BLSSM with inverse seesaw the g−2 may receive new contributions, in addition to the usual MSSM ones, due to the extensi...