Search

We review the role played by the ‘μ from ν’ supersymmetric standard model (μνSSM) in the search for supersymmetry. First, we discuss its theoretical motivation, that is the simultaneous solution of μ- and ν-problems through the introduction of right-handed neutrinos. The latter produces R-parity violation (RPV), giving rise to interesting signals of new physics. As by-products, in the μνSSM there are dark matter candidates, and electroweak baryogenesis can be realized. Then, we survey signals by which the model could be tested at the large hadron collider (LHC). In addition to the enlarged Higgs sector with sneutrinos, we put special emphasis in analyzing the intimate connection between the lightest supersymmetric particle (LSP) lifetime and the size of neutrino Yukawa couplings. Displaced vertices and/or multileptons are some of the interesting signatures that can be probed. Finally, we discuss possible extensions of the μνSSM such as the inclusion in the superpotential of the conventional trilinear lepton-number violating couplings, the addition of an extra U(1)′ gauge group to the symmetry of the standard model, or the reinterpretation of the Higgs doublets as a fourth family of leptons superfields motivating the existence of a fourth family of vector-like quark doublet superfields. Fil: Lopez, Daniel Elbio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Muñoz, Carlos. Grupo de Aprendizaje Automatico ; Escuela Politecnica Superior ; Universidad Autonoma de Madrid

Journal of high energy physics 08(8), 068 (2022). doi:10.1007/JHEP08(2022)068, We present version 2 of SModelS, a program package for the fast reinterpretation of LHC searches for new physics on the basis of simplified model results. The major novelty of the SModelS v2 series is an extended topology description with a flexible number of particle attributes, such as spin, charge, decay width, etc. This enables, in particular, the treatment of a wide range of signatures with long-lived particles. Moreover, constraints from prompt and long-lived searches can be evaluated simultaneously in the same run. The current database includes results from searches for heavy stable charged particles, disappearing tracks, displaced jets and displaced leptons, in addition to a large number of prompt searches. The capabilities of the program are demonstrated by two physics applications: constraints on long-lived charged scalars in the scotogenic model, and constraints on the electroweak-ino sector in the Minimal Supersymmetric Standard Model., Published by SISSA, [Trieste]

We study colored Higgsino-mediated proton decay (dimension-five proton decay) in a model based on the flipped $SU(5)$ GUT. In the model, the GUT-breaking ${\bf10}$, ${\bf \overline{10}}$ fields have a GUT-scale mass term and gain VEVs through higher-dimensional operators, which induces an effective mass term between the color triplets in the ${\bf 5}$, ${\bf \bar{5}}$ Higgs fields that is not much smaller than the GUT scale. This model structure gives rise to observable dimension-five proton decay, and at the same time achieves moderate suppression on dimension-five proton decay that softens the tension with the current bound on $\Gamma(p\to K^+\nu)$. We investigate the flavor dependence of the Wilson coefficients of the operators relevant to dimension-five proton decay, by relating them with diagonalized Yukawa couplings and CKM matrix components in MSSM, utilizing the fact that the GUT Yukawa couplings are in one-to-one correspondence with the MSSM Yukawa couplings in flipped models. Then we numerically evaluate the Wilson coefficients, and predict the distributions of the ratios of the partial widths of various proton decay modes., Comment: 22 pages, 2 figures. Version accepted for publication in JHEP

Gluino-SUGRA ($\tilde{g}$SUGRA), which is an economical extension of the predictive mSUGRA, adopts much heavier gluino mass parameter than other gauginos mass parameters and universal scalar mass parameter at the unification scale. It can elegantly reconcile the experimental results on the Higgs boson mass, the muon $g-2$, the null results in search for supersymmetry at the LHC and the results from B-physics. In this work, we propose several new ways to generate large gaugino hierarchy (i.e. $M_3\gg M_1,M_2$) for $\tilde{g}$SUGRA model building and then discuss in detail the implications of the new muon $g-2$ results with the updated LHC constraints on such $\tilde{g}$SUGRA scenarios. We obtain the following observations: (i) For the most interesting $M_1=M_2$ case at the GUT scale with a viable bino-like dark matter, the $\tilde{g}$SUGRA can explain the muon $g-2$ anomaly at $1\sigma$ level and be consistent with the updated LHC constraints for $6\leq M_3/M_1 \leq 9$ at the GUT scale; (ii) For $M_1:M_2=5:1$ at the GUT scale with wino-like dark matter, the $\tilde{g}$SUGRA model can explain the muon $g-2$ anomaly at $2\sigma$ level and be consistent with the updated LHC constraints for $3\leq M_3/M_1 \leq 3.2$ at the GUT scale; (iii) For $M_1:M_2=3:2$ at the GUT scale with mixed bino-wino dark matter, the $\tilde{g}$SUGRA model can explain the muon $g-2$ anomaly at $1\sigma$ level and be consistent with the updated LHC constraints for $6.9\leq M_3/M_1 \leq 7.5$ at the GUT scale. Although the choice of heavy gluino will always increase the FT involved, some of the $1\sigma/2\sigma$ survived points of $\Delta a_\mu^{combine}$ can still allow low EWFT of order several hundreds and be fairly natural. Constraints from (dimension-five operator induced) proton decay are also discussed., Comment: Major changes, 29 pages, 7 figures, Published version in JHEP

While the observation of nucleon decay would be a smoking gun of Grand Unified Theories (GUTs) in general, the ratios between the decay rates of the various channels carry rich information about the specific GUT model realization. To investigate this fingerprint of GUT models in the context of supersymmetric (SUSY) GUTs, we present the software tool \texttt{SusyTCProton}, which is an extension of the module \texttt{SusyTC} to be used with the \texttt{REAP} package. It allows to calculate nucleon decay rates from the relevant dimension five GUT operators specified at the GUT scale, including the full loop-dressing at the SUSY scale. As an application, we investigate the fingerprints of two example GUT toy models with different flavor structures, performing an MCMC analysis to include the experimental uncertainties for the charged fermion masses and CKM mixing parameters. While both toy models provide equally good fits to the low energy data, we show how they could be distinguished via their predictions of ratios for nucleon decay rates. Together with \texttt{SusyTCProton} we also make the additional module \texttt{ProtonDecay} public. It can be used independently from \texttt{REAP} and allows to calculate nucleon decay rates from given $D=5$ and $D=6$ operator coefficients (accepting the required SUSY input for the $D=5$ case in SLHA format). The $D=6$ functionality can also be used to calculate nucleon decay in non-SUSY GUTs., Note: 34 pages, 6 figures, 5 tables. The packages ProtonDecay and SusyTCProton can be downloaded from http://particlesandcosmology.unibas.ch/downloads/protondecay.html

By extending a previously proposed conformal gauge mediation model, we construct a gauge-mediated SUSY breaking (GMSB) model where a SUSY-breaking scale, a messenger mass, the $\mu$-parameter and the gravitino mass in a minimal supersymmetric (SUSY) Standard Model (MSSM) are all explained by a single mass scale, a R-symmetry breaking scale. We focus on a low scale SUSY-breaking scenario with the gravitino mass $m_{3/2}=\mathcal{O}(1){\rm eV}$, which is free from the cosmological gravitino problem and relaxes the fine-tuning of the cosmological constant. Both the messenger and SUSY-breaking sectors are subject to a hidden strong dynamics with the conformality above the messenger mass threshold (and hence the name of the model "strongly interacting conformal gauge mediation"). In our model, the Higgs B-term is suppressed and a large $\tan\beta$ is predicted, resulting in the relatively light second CP-even Higgs and the CP-odd Higgs with a sizable production cross section. These Higgs bosons can be tested at future LHC experiments., Comment: 8 pages, 2 figures, 1 table

We propose a baryogenenesis mechanism that uses a rotating condensate of a Peccei-Quinn (PQ) symmetry breaking field and the dimension-five operator that gives Majorana neutrino masses. The rotation induces charge asymmetries for the Higgs boson and for lepton chirality through sphaleron processes and Yukawa interactions. The dimension-five interaction transfers these asymmetries to the lepton asymmetry, which in turn is transferred into the baryon asymmetry through the electroweak sphaleron process. QCD axion dark matter can be simultaneously produced by dynamics of the same PQ field via kinetic misalignment or parametric resonance, favoring an axion decay constant $f_a \lesssim 10^{10}$ GeV, or by conventional misalignment and contributions from strings and domain walls with $f_a \sim 10^{11}$ GeV. The size of the baryon asymmetry is tied to the mass of the PQ field. In simple supersymmetric theories, it is independent of UV parameters and predicts the supersymmtry breaking mass scale to be $\mathcal{O}(10-10^4)$ TeV, depending on the masses of the neutrinos and whether the condensate is thermalized during a radiation or matter dominated era. We also construct a theory where TeV scale supersymmetry is possible. Parametric resonance may give warm axions, and the radial component of the PQ field may give signals in rare kaon decays from mixing with the Higgs and in dark radiation., Comment: 71 pages, 6 Figures

We consider a supersymmetric type-I seesaw framework with non-universal scalar masses at the GUT scale to explain the long-standing discrepancy of the anomalous magnetic moment of the muon. We find that it is difficult to accommodate the muon g-2 while keeping charged-lepton flavor violating processes under control for the conventional SO(10)-based relation between the up sector and neutrino sector. However, such tension can be relaxed by adding a Georgi-Jarlskog factor for the Yukawa matrices, which requires a non-trivial GUT-based model. In this model, we find that both observables are compatible for small mixings, CKM-like, in the neutrino Dirac Yukawa matrix., AM acknowledges support from La-Caixa-Severo Ochoa scholarship. AM and OV are supported by Spanish and European funds under MICIU Grant FPA2017-84543-P and by the \Centro de Excelencia Severo Ochoa" programme under grant SEV-2014-0398. OV acknowledges partial support from the \Generalitat Valenciana" grant PROMETEO2017- 033. JMY acknowledges funding from the National Natural Science Foundation of China (NNSFC) under grant Nos.11675242, 11821505, and 11851303, from Peng-Huan-Wu Theoretical Physics Innovation Center (11947302), from the CAS Center for Excellence in Particle Physics (CCEPP), from the CAS Key Research Program of Frontier Sciences and from a Key R&D Program of Ministry of Science and Technology under number 2017YFA0402204. LW acknowledges funding from the National Natural Science Foundation of China (NNSFC) under grant No. 11705093.

In some models of thermal relic dark matter, the relic abundance may be set by inelastic scattering processes (rather than annihilations) becoming inefficient as the universe cools down. This effect has been called coscattering. We present a procedure to numerically solve the full momentum-dependent Boltzmann equations in coscattering, which allows for a precise calculation of the dark matter relic density including the effects of early kinetic decoupling. We apply our method to a simple model, containing a fermionic SU(2) triplet and a fermionic singlet with electroweak-scale masses, at small triplet-singlet mixing. The relic density can be set by either coannihilation or, at values of the mixing angle $\theta\lesssim 10^{-5}$, by coscattering. We identify the parameter ranges which give rise to the observed relic abundance. As a special case, we study bino-like dark matter in split supersymmetry at large $\mu$., Comment: 17 pages, 4 figures; v2: references added, matches journal version

In this paper, motivated by the observation that the Standard Model predictions are now above the experimental data for the mass difference ΔM s(d), we perform a detailed study of B s(d) − $$ \overline{B} $$ B ¯ s(d) mixing and B s → μ + μ − decay in the ℤ 3-invariant NMSSM with non-minimal flavour violation, using the recently developed procedure based on the Flavour Expansion Theorem, with which one can perform a purely algebraic mass-insertion expansion of an amplitude written in the mass eigenstate basis without performing any diagrammatic calculations in the interaction/flavour basis. Specifically, we consider the finite orders of mass insertions for neutralinos but the general orders for squarks and charginos, under two sets of assumptions for the squark flavour structures (i.e., while the flavour-conserving off-diagonal element δ 33 LR is kept in both of these two sectors, only the flavour-violating off-diagonal elements δ 23 LL and δ i3 RR (i = 1, 2) are kept in the LL and RR sectors, respectively). Our analytic results are then expressed directly in terms of the initial Lagrangian parameters in the interaction/flavour basis, making it easy to impose the experimental bounds on them. It is found numerically that the NMSSM effects with the above two assumptions for the squark flavour structures can accommodate the observed deviation for ΔM s(d), while complying with the experimental constraints from the branching ratios of B s → μ + μ − and B → X s γ decays.

We propose a minimal Yukawa deflection scenario of AMSB from the Kahler potential through the Higgs-messenger mixing. Salient features of this scenario are discussed and realistic MSSM spectrum can be obtained. Such a scenario, which are very predictive, can solve the tachyonic slepton problem with less messenger species. Numerical results indicate that the LOSPs predicted by this scenario can not be good DM candidates. So it is desirable to extend this scenario with a Peccei-Quinn sector to solve the strong CP problem and at the same time provide new DM candidates. We propose a way to obtain a light axino mass in SUSY KSVZ axion model with Yukawa deflected anomaly mediation SUSY breaking mechanism. The axino can possibly be the LSP and act as a good DM candidate., Minor changes, published version. 25 pages, 6 figures

The ACME collaboration has recently announced a new constraint on the electron EDM, $|d_e| < 1.1 \times 10^{-29}\, e\, {\rm cm}$, from measurements of the ThO molecule. This is a powerful constraint on CP-violating new physics: even new physics generating the EDM at two loops is constrained at the multi-TeV scale. We interpret the bound in the context of different scenarios for new physics: a general order-of-magnitude analysis for both the electron EDM and the CP-odd electron-nucleon coupling; 1-loop SUSY, probing sleptons above 10 TeV; 2-loop SUSY, probing multi-TeV charginos or stops; and finally, new physics that generates the EDM via the charm quark or top quark Yukawa couplings. In the last scenario, new physics generates a "QULE operator" $(q_f \bar{\sigma}^{\mu \nu}{\bar u}_f) \cdot (\ell {\bar{\sigma}}_{\mu \nu} {\bar e})$, which in turn generates the EDM through RG evolution. If the QULE operator is generated at tree level, this corresponds to a previously studied leptoquark model. For the first time, we also classify scenarios in which the QULE operator is generated at one loop through a box diagram, which include SUSY and leptoquark models. The electron EDM bound is the leading constraint on a wide variety of theories of CP-violating new physics interacting with the Higgs boson or the top quark. We argue that any future nonzero measurement of an electron EDM will provide a strong motivation for constructing new colliders at the highest feasible energies., Comment: 23 pages plus appendices, 16 figures

In Higgs portal models of fermion dark matter, scalar couplings are unavoidably suppressed by strong bounds from direct detection experiments. As a consequence, thermal dark matter relics must coexist with mediators in a compressed spectrum of dark particles. Small couplings and small mass splittings lead to slow mediator decays, leaving signatures with displaced vertices or disappearing tracks at colliders. We perform a comprehensive analysis of long-lived mediators at the LHC in the context of a minimal dark matter model with a naturally small Higgs portal, also known as the wino-bino scenario in supersymmetry. Existing searches for disappearing charged tracks and displaced hard leptons already exclude tiny portal couplings that cannot be probed by current direct and indirect detection experiments. For larger portal couplings, we predict new signatures with displaced soft leptons, which are accessible with run-II data. Searches for displaced particles are sensitive to weakly coupling mediators with masses up to the TeV scale, well beyond the reach of prompt signals., 18 pages, 7 figures, matches version published in JHEP

We examine the sensitivity at a future 100 TeV proton-proton collider to compressed dark sectors whose decay products are invisible due to below-threshold energies and/or small couplings to the Standard Model. This scenario could be relevant to models of WIMP dark matter, where the lightest New Physics state is an (isolated) electroweak multiplet whose lowest component is stable on cosmological timescales. We rely on the additional emission of a hard on-shell $Z$-boson decaying to leptons, a channel with low background systematics, and include a careful estimate of the real and fake backgrounds to this process in our analysis. We show that an integrated luminosity of 30 ab$^{-1}$ would allow exclusion of a TeV-scale compressed dark sector with inclusive production cross section of 0.3 fb, for 1\% background systematic uncertainty and splittings below 5 GeV. This translates to exclusion of a pure higgsino (wino) multiplet with mass of 500 (970) GeV., Comment: 22 pages, 9 figures

It is pointed out that in supersymmetric models with a new gauge symmetry under which the Higgs is charged, the fine-tuning of the electroweak symmetry breaking is relaxed due to suppression of the top Yukawa coupling at higher scales by a new large gauge coupling. We calculate the fine-tuning in an explicit model and find that the lower bounds on stops and gluino masses from the naturalness criterion are increased by several hundred GeV in comparison to the Minimal Supersymmetric Standard Model (MSSM). The fine-tuning is improved by one to two orders of magnitude as compared to the MSSM, as a consequence of both the suppression of the top Yukawa coupling and the additional tree-level contribution to the Higgs mass allowing for much lighter stops., 17 pages, 3 figures

We examine the parameter space of supersymmetric models with R-parity violating interactions of the form λ′ LQD c to explain the various anomalies observed in b → sℓℓ transitions. To generate the appropriate operator in the low energy theory, we are led to a region of parameter space where loop contributions dominate. In particular, we concentrate on parameters for which diagrams involving winos, which have not been previously considered, give large contributions. Many different potentially constraining processes are analyzed, including $$ \tau \to \mu \mu \mu, {B}_s-{\overline{B}}_s $$ τ → μ μ μ , B s − B ¯ s mixing, $$ B\to {K}^{\left(\ast \right)}\nu \overline{\nu} $$ B → K ∗ ν ν ¯ , Z decays to charged leptons, and direct LHC searches. We find that it is possible to explain the anomalies, but it requires large values of λ′, which lead to relatively low Landau poles.

We study the prospects of observing the non-resonant di-Higgs pair production in the Standard Model (SM) at the high luminosity run of the 14 TeV LHC (HL-LHC), upon combining multiple final states chosen on the basis of their yield and cleanliness. In particular, we consider the $b\bar{b}\gamma \gamma, b\bar{b} \tau^+ \tau^-, b\bar{b} WW^*, WW^*\gamma \gamma$ and $4W$ channels mostly focusing on final states with photons and/or leptons and study 11 final states. We employ multivariate analyses to optimise the discrimination between signal and backgrounds and find it performing better than simple cut-based analyses. The various differential distributions for the Higgs pair production have non-trivial dependencies on the Higgs self-coupling ($\lambda_{hhh}$). We thus explore the implications of varying $\lambda_{hhh}$ for the most sensitive search channel for the double Higgs production, \textit{viz.}, $b\bar{b}\gamma\gamma$. The number of signal events originating from SM di-Higgs production in each final state is small and for this reason measurement of differential distributions may not be possible. Furthermore, we consider various physics beyond the standard model scenarios to quantify the effects of contamination while trying to measure the SM di-Higgs signals in detail. In particular, we study generic resonant heavy Higgs decays to a pair of SM-like Higgs bosons or to a pair of top quarks, heavy pseudoscalar decaying to an SM-like Higgs and a $Z$-boson, charged Higgs production in association with a top and a bottom quark and also various well-motivated supersymmetric channels. We set limits on the cross-sections for the aforementioned new physics scenarios, above which these can be seen as excesses over the SM background and affect the measurement of Higgs quartic coupling. We also discuss the correlations among various channels which can be useful to identify the new physics model., Comment: Version 2; 70 pages, 17 figures and 26 tables; version accepted for publication in JHEP

Long-lived light particles (LLLPs) appear in many extensions of the standard model. LLLPs are usually motivated by the observed small neutrino masses, by dark matter or both. Typical examples for fermionic LLLPs (a.k.a. heavy neutral fermions, HNFs) are sterile neutrinos or the lightest neutralino in R-parity violating supersymmetry. The high luminosity LHC is expected to deliver up to 3/ab of data. Searches for LLLPs in dedicated experiments at the LHC could then probe the parameter space of LLLP models with unprecedented sensitivity. Here, we compare the prospects of several recent experimental proposals, FASER, CODEX-b and MATHUSLA, to search for HNFs and discuss their relative merits., 21 pages, 6 figures; v2:references and minor comments added, plots updated

Many extensions of the standard model (SM) involve new massive particles charged under the electroweak gauge symmetry. The electroweakly interacting new particles affect various SM processes through radiative corrections. We discuss the possibility of detecting such new particles based on the precise measurement of the SM processes at high energy hadron colliders. It then turns out that Drell-Yan processes receive radiative corrections from the electroweakly interacting particles at the level of ${\cal O}$(0.1-10) %. It is hence possible to indirectly search for the Higgsino up to the mass of 400 GeV and the quintet (5-plet) Majorana fermion up to the mass of 1200 GeV at the high-luminosity running of the Large Hadron Collider, if the systematic uncertainty associated with the estimation of the SM background becomes lower than the statistical one., 11 pages, 4 figures

Dismissing traditional naturalness concerns while embracing the Higgs boson mass measurement and unification motivates careful analysis of trans-TeV supersymmetric theories. We take an effective field theory (EFT) approach, matching the Minimal Supersymmetric Standard Model (MSSM) onto the Standard Model (SM) EFT by integrating out heavy superpartners, and evolving MSSM and SMEFT parameters according to renormalization group equations in each regime. Our matching calculation is facilitated by the recent covariant diagrams formulation of functional matching techniques, with the full one-loop SUSY threshold corrections encoded in just 30 diagrams. Requiring consistent matching onto the SMEFT with its parameters (those in the Higgs potential in particular) measured at low energies, and in addition requiring unification of bottom and tau Yukawa couplings at the scale of gauge coupling unification, we detail the solution space of superpartner masses from the TeV scale to well above. We also provide detailed views of parameter space where Higgs coupling measurements have probing capability at future colliders beyond the reach of direct superpartner searches at the LHC., 59 pages, 8 figures; v2: references and minor clarifications added

R-parity and baryon number violating operators can be allowed in the Supersymmetric Standard Model and thus lead to interesting baryon number violating processes such as neutron-antineutron oscillations and baryogenesis of the Universe via the decay of the lightest supersymmetric particle (LSP). Adopting the LSP baryogenesis mechanism realized by the late decay of the axino, we identify a single coupling lambda''_313 as a common origin for the matter-antimatter asymmetry of the Universe as well as potentially observable neutron-antineutron oscillation rates. From this, rather strong constraints on the supersymmetry breaking masses and the axion decay constant are obtained. The favoured parameter space of lambda''_313 ~ 0.1 and sub-TeV masses for the relevant sparticles is readily accessible by the current and future LHC searches., Comment: 17 pages, 6 figures, added references, version accepted for publication in JHEP

It is well known that the annihilation of Majorana dark matter into fermions is helicity suppressed. Here, we point out that the underlying mechanism is a subtle combination of two distinct effects, and we present a comprehensive analysis of how the suppression can be partially or fully lifted by the internal bremsstrahlung of an additional boson in the final state. As a concrete illustration, we compute analytically the full amplitudes and annihilation rates of supersymmetric neutralinos to final states that contain any combination of two standard model fermions, plus one electroweak gauge boson or one of the five physical Higgs bosons that appear in the minimal supersymmetric standard model. We classify the various ways in which these three-body rates can be large compared to the two-body rates, identifying cases that have not been pointed out before. In our analysis, we put special emphasis on how to avoid the double counting of identical kinematic situations that appear for two-body and three-body final states, in particular on how to correctly treat differential rates and the spectrum of the resulting stable particles that is relevant for indirect dark matter searches. We find that both the total annihilation rates and the yields can be significantly enhanced when taking into account the corrections computed here, in particular for models with somewhat small annihilation rates at tree-level which otherwise would not be testable with indirect dark matter searches. Even more importantly, however, we find that the resulting annihilation spectra of positrons, neutrinos, gamma-rays and antiprotons differ in general substantially from the model-independent spectra that are commonly adopted, for these final states, when constraining particle dark matter with indirect detection experiments., Comment: 64 pages with jheppub.sty, 15 figures and 12 tables. Slightly extended discussion + minor updates to match published version

We study the phenomenology of models of electroweak symmetry breaking where the Higgs potential is dominated by a positive quadratic term destabilized by a tadpole arising from the coupling to an "auxiliary" Higgs sector. The auxiliary Higgs sector can be either perturbative or strongly coupled, similar to technicolor models. Since electroweak symmetry breaking is driven by a tadpole, the cubic and quartic Higgs couplings can naturally be significantly smaller than their values in the standard model. The theoretical motivation for these models is that they can explain the 125 GeV Higgs mass in supersymmetry without fine-tuning. The auxiliary Higgs sector contains additional Higgs states that cannot decouple from standard model particles, so these models predict a rich phenomenology of Higgs physics beyond the standard model. In this paper we analyze a large number of direct and indirect constraints on these models. We present the current constraints after the 8 TeV run of the LHC, and give projections for the sensitivity of the upcoming 14 TeV run. We find that the strongest constraints come from the direct searches $A^0 \to Zh$, $A^0 \to t\bar{t}$, with weaker constraints from Higgs coupling fits. For strongly-coupled models, additional constraints come from $\rho^+ \to WZ$ where $\rho^+$ is a vector resonance. Our overall conclusion is that a significant parameter space for such models is currently open, allowing values of the Higgs cubic coupling down to 0.4 times the standard model value for weakly coupled models and vanishing cubic coupling for strongly coupled models. The upcoming 14 TeV run of the LHC will stringently test this scenario and we identify several new searches with discovery potential for this class of models., Comment: 35 pages, 10 figures

In supersymmetric models, a correlation exists between the structure of the Higgs sector quartic potential and the coupling of the lightest CP-even Higgs to fermions and gauge bosons. We exploit this connection to relate the observed value of the Higgs mass ~ 125 GeV to the magnitude of its couplings. We analyze different scenarios ranging from the MSSM with heavy stops to more natural models with additional non-decoupling D-term/F-term contributions. A comparison with the most recent LHC data, allows to extract bounds on the heavy Higgs boson masses, competitive with bounds from direct searches., Comment: 14 pages plus appendix; 9 figures

We compute analytically the tree-level annihilation rates of a collection of non-relativistic neutralino and chargino two-particle states in the general MSSM, including the previously unknown off-diagonal rates. The results are prerequisites to the calculation of the Sommerfeld enhancement in the MSSM, which will be presented in subsequent work. They can also be used to obtain concise analytic expressions for MSSM dark matter pair annihilation in the present Universe for a large number of exclusive two-particle final states., We would like to thank N. Baro for discussions and some cross checks of the tree-level annihilation cross sections with the private code Sloops [11, 12, 29]. The work of M. B. was supported in part by the DFG Sonderforschungsbereich/Transregio 9 "Computergestutzte Theoretische Teilchenphysik". C. H. greatly acknowledges the support by the "Deutsche Telekom Stiftung". The work of P. R. is partially supported by MEC (Spain) under grants FPA2007-60323 and FPA2011-23778 and by the Spanish Consolider-Ingenio 2010 Programme CPAN (CSD2007-00042). Feynman diagrams have been drawn with the packages AXODRAW [30] and JAXODRAW [31].

22 páginas, 5 figuras.-- El Pdf es la versión pre-print: arXiv:1010.5751v1, We give a straightforward procedure to scan the seesaw parameter-space, using the common “R-parametrization”, in a complete way. This includes a very simple rule to incorporate the perturbativity requirement as a condition for the entries of the R-matrix. As a relevant application, we show that the somewhat propagated belief that BR(μ → e, γ) in supersymmetric seesaw models depends strongly on the value of θ 13 is an “optical effect” produced by incomplete scans, and does not hold after a careful analytical and numerical study. When the complete scan is done, BR(μ → e, γ) gets very insensitive to θ 13. This holds even if the right-handed neutrino masses are kept constant or under control (as is required for succesful leptogenesis). In most cases the values of BR(μ → e, γ) are larger than the experimental upper bound. Including (unflavoured) leptogenesis does not introduce any further dependence on θ 13, although decreases the typical value of BR(μ → e, γ)., This work has been partially supported by the MICINN, Spain, under contracts FPA-2007-60252 and FPA-2007-60323; Consolider- Ingenio PAU CSD2007-00060 and MULTIDARK CSD2009-00064. We thank as well the Generalitat Valenciana grants PROMETEO/2009/116 and PROMETEO/2008/069; the Comunidad de Madrid through Proyecto HEPHACOS ESP-1473 and the European Commission under contract PITN-GA-2009-237920. B. Zaldívar acknowledges the fi nancial support of a FPI (MICINN) grant, with reference BES-2008-004688.

Previous LHC forecasts for the constrained minimal supersymmetric standard model (CMSSM), based on current astrophysical and laboratory measurements, have used priors that are flat in the parameter tan beta, while being constrained to postdict the central experimental value of MZ. We construct a different, new and more natural prior with a measure in mu and B (the more fundamental MSSM parameters from which tan beta and MZ are actually derived). We find that as a consequence this choice leads to a well defined fine-tuning measure in the parameter space. We investigate the effect of such on global CMSSM fits to indirect constraints, providing posterior probability distributions for Large Hadron Collider (LHC) sparticle production cross sections. The change in priors has a significant effect, strongly suppressing the pseudoscalar Higgs boson dark matter annihilation region, and diminishing the probable values of sparticle masses. We also show how to interpret fit information from a Markov Chain Monte Carlo in a frequentist fashion; namely by using the profile likelihood. Bayesian and frequentist interpretations of CMSSM fits are compared and contrasted., 26 pages, 38 figures, revised version 3 has added results on the frequentist interpretation: an additional section, and author

The discovery potential of the LHC is investigated for the minimal anomaly-mediated supersymmetry breaking (mAMSB) scenario, using the ATLAS fast detector simulator, including track reconstruction and particle identification. Generic supersymmetry search cuts are used to map the 5-sigma (and >=10 event) discovery contours in the m_0 - m_3/2 plane. With 100 inverse fb of integrated luminosity the search will reach up to 2.8 TeV in the squark mass and 2.1 TeV in the gluino mass. We generalise a kinematical variable and demonstrate that it is sensitive to the small chargino-LSP mass splitting characteristic of AMSB models. By identifying tracks from chargino decays we show that the Wino-like nature of the LSP can be determined for a wide range of chargino lifetimes., 46 pages, 18 figures, added references

We demonstrate that some of the suggested five supergravity points for study at the LHC could be approximately derived from perturbative string theories or M-theory, but that charge and colour breaking minima would result. As a pilot study, we then analyse a perturbative string model with non-universal soft masses that are optimised in order to avoid global charge and colour breaking minima. By combining measurements of up to six kinematic edges from squark decay chains with data from a new kinematic variable, designed to improve slepton mass measurements, we demonstrate that a typical LHC experiment will be able to determine squark, slepton and neutralino masses with an accuracy sufficient to permit an optimised model to be distinguished from a similar standard SUGRA point. The technique thus generalizes SUSY searches at the LHC., Comment: 31 pages, 15 figures. To be submitted to JHEP. Changes: one reference is added, format of Table 4 is altered, treatment of llq-Edge is extended to include all special cases

We derive and present expressions for the kinematic endpoints that arise in the invariant mass distributions of visible decay products of cascade decays featuring a two body decay followed by a three body decay. This is an extension of a current technique that addresses chains of successive two body decays. We then apply these to a supergravity model with Non-Universal Higgs Masses (NUHM), having simulated a data set using the ATLFAST detector simulation. We find that, should such a model be chosen by nature, the endpoints will be visible in ATLAS data, and we discuss the problems associated with mass reconstruction in models with a similar phenomenology., Comment: 21 pages, 13 figures, updated the preprint number to reflect status as an ATLAS scientific note

We present an extensive analysis of rare K decays, in particular of the two neutrino modes K+->pi+ nu nu-bar and KL->pi0 nu nu-bar, in the Minimal Supersymmetric extension of the Standard Model. We analyse the expectations for the branching ratios of these modes, both within the restrictive framework of the minimal flavour violation hypothesis and within a more general framework with new sources of flavour-symmetry breaking. In both scenarios, the information that can be extracted from precise measurements of the two neutrino modes turn out to be very useful in restricting the parameter space of the model, even after taking into account the possible information on the mass spectrum derived from high-energy colliders, and the constraints from B-physics experiments. In the presence of new sources of flavour-symmetry breaking, additional significant constraints on the model can be derived also from the two KL->pi0 l+l- modes., 22 pages, 10 figures (high quality figures available on request)

The detection of the flavour content of jets produced from R-parity violating neutralino decays is investigated in the case where one baryon-number violating coupling dominates. Simulations are performed of the ATLAS experiment at the LHC for all couplings, other than lambda"_tjk since neutralino decays through these couplings are very suppressed. Secondary vertex distributions and muons produced by heavy-quark (b- and c-) jets allow discrimination between LSP decay modes. The dominant coupling can be identified at better than 3.5 sigma in almost all cases, with the only remaining ambiguity caused by the inability to distinguish strange from down quarks., 10 pages, 3 figures

金沢大学理工研究域数物科学系, We propose a solution to the μ-problem due to the non-universal soft supersymmetry breaking in a class of supersymmetric extensions of the SM with an extra U(1) and the NMSSM. Our scenario resembles to an earlier one which has been proposed as a solution to the μ-problem in the framework of similar models but it has rather different features from that. Theoretically crucial points in the present scenario are the realization of the required non-universal soft supersymmetry breaking parameters and the concern to avoid the vacuum instability due to tadpoles. We discuss them in some detail. In particular, on the non-universal soft supersymmetry breaking we discuss the superstring and the field theory with reduction of couplings possibilities. We also study the weak scale radiative symmetry breaking in the considered models and estimate the upper mass bound of the lightest neutral Higgs scalar. The latter tends to be smaller in the present scenario as compared to the previous one., CC-BY 4.0