U(1)B3−L2U(1)_{B_3-L_2} Explanation of the Neutral Current B−B-Anomalies

We investigate a speculative short-distance force, proposed to explain discrepancies observed between measurements of certain neutral current decays of $B$ hadrons and their Standard Model predictions. The force derives from a spontaneously broken, gauged $U(1)_{B_3-L_2}$ extension to the Standard Model, where the extra quantum numbers of Standard Model fields are given by third family baryon number minus second family lepton number. The only fields beyond those of the Standard Model are three right-handed neutrinos, a gauge field associated with $U(1)_{B_3-L_2}$ and a Standard Model singlet complex scalar which breaks $U(1)_{B_3-L_2}$, a `flavon'. This simple model, via interactions involving a TeV scale force-carrying $Z^\prime$ vector boson, can successfully explain the neutral current $B-$anomalies whilst accommodating other empirical constraints. In an ansatz for fermion mixing, a combination of up-to-date $B-$anomaly fits, LHC direct $Z^\prime$ search limits and other bounds rule out the domain 0.15 TeV$< M_{Z^\prime} <$ 1.9 TeV at the 95$\%$ confidence level. For more massive $Z^\prime$s, the model possesses a {\em flavonstrahlung}\ signal, where $pp$ collisions produce a $Z^\prime$ and a flavon, which subsequently decays into two Higgs bosons

The impact of the ATLAS zero-lepton, jets and missing momentum search on a CMSSM fit

Recent ATLAS data significantly extend the exclusion limits for supersymmetric particles. We examine the impact of such data on global fits of the constrained minimal supersymmetric standard model (CMSSM) to indirect and cosmological data. We calculate the likelihood map of the ATLAS search, taking into account systematic errors on the signal and on the background. We validate our calculation against the ATLAS determinaton of 95% confidence level exclusion contours. A previous CMSSM global fit is then re-weighted by the likelihood map, which takes a bite at the high probability density region of the global fit, pushing scalar and gaugino masses up.Comment: 16 pages, 7 figures. v2 has bigger figures and fixed typos. v3 has clarified explanation of our handling of signal systematic

Uncertainties in the lightest CP even Higgs boson mass prediction in the minimal supersymmetric standard model: fixed order versus effective field theory prediction

We quantify and examine the uncertainties in predictions of the lightest $CP$ even Higgs boson pole mass $M_h$ in the Minimal Supersymmetric Standard Model (MSSM), utilising current spectrum generators and including some three-loop corrections. There are two broadly different approximations being used: effective field theory (EFT) where an effective Standard Model (SM) is used below a supersymmetric mass scale, and a fixed order calculation, where the MSSM is matched to QCD$\times$QED at the electroweak scale. The uncertainties on the $M_h$ prediction in each approach are broken down into logarithmic and finite pieces. The inferred values of the stop mass parameters are sensitively dependent upon the precision of the prediction for $M_h$. The fixed order calculation appears to be more accurate below a supersymmetry (SUSY) mass scale of $M_S \approx 1.2$ TeV, whereas above this scale, the EFT calculation is more accurate. We also revisit the range of the lightest stop mass across fine-tuned parameter space that has an appropriate stable vacuum and is compatible with the lightest $CP$ even Higgs boson $h$ being identified with the one discovered at the ATLAS and CMS experiments in 2012; we achieve a maximum value of $\sim 10^{11}$ GeV

The calculation of sparticle and Higgs decays in the minimal and next-to-minimal supersymmetric standard models: SOFTSUSY4.0

We describe a major extension of the SOFTSUSY spectrum calculator to include the calculation of the decays, branching ratios and lifetimes of sparticles into lighter sparticles, covering the next-to-minimal supersymmetric standard model (NMSSM) as well as the minimal supersymmetric standard model (MSSM). This document acts as a manual for the new version of SOFTSUSY, which includes the calculation of sparticle decays. We present a comprehensive collection of explicit expressions used by the program for the various partial widths of the different decay modes in the appendix

Measuring smuon-selectron mass splitting at the CERN LHC and patterns of supersymmetry breaking

With sufficient data, Large Hadron Collider (LHC) experiments can constrain the selectron-smuon mass splitting through differences in the di-electron and di-muon edges from supersymmetry (SUSY) cascade decays. We study the sensitivity of the LHC to this mass splitting, which within mSUGRA may be constrained down to O(10^{-4}) for 30 fb^{-1} of integrated luminosity. Over substantial regions of SUSY breaking parameter space the fractional edge splitting can be significantly enhanced over the fractional mass splitting. Within models where the selectron and smuon are constrained to be universal at a high scale, edge splittings up to a few percent may be induced by renormalisation group effects and may be significantly discriminated from zero. The edge splitting provides important information about high-scale SUSY breaking terms and should be included in any fit of LHC data to high-scale models

Erratum to: U (1 ) B 3 - L 2 explanation of the neutral current B- anomalies (The European Physical Journal C, (2021), 81, 1, (56), 10.1140/epjc/s10052-021-08855-w)

A Correction to this paper has been published https://doi.org/10.1140/epjc/s10052-021-08855-w</jats:p

The dark side of mSUGRA

We study the mu<0 branch of the minimal supergravity ansatz of the minimal supersymmetric standard model. The extent to which mu<0 is disfavoured compared to mu>0 in global fits is calculated with Markov Chain Monte Carlo methods and bridge sampling. The fits include state-of-the-art two-loop MSSM contributions to the electroweak observables M_W and sin^2 theta_w^l, as well as the anomalous magnetic moment of the muon (g-2)_mu, the relic density of dark matter and other relevant indirect observables. mu<0 is only marginally disfavoured in global fits and should be considered in mSUGRA analyses. We estimate that the ratio of probabilities is P(mu0)=0.07-0.16