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## Search for neutral minimal supersymmetric standard model Higgs bosons decaying to tau pairs produced in association with b quarks in pp̄ collisions at √s=1.96TeV

Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Aoki, M.; Arov, M.; Askew, A.; Åsman, B.; Atramentov, O.; Avila, C.; Backusmayes, J.; Badaud, F.; Bagby, L.; Baldin, B.;
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
75.97%
We report results from a search for neutral Higgs bosons produced in association with b quarks using data recorded by the D0 experiment at the Fermilab Tevatron Collider and corresponding to an integrated luminosity of 7.3fb-1. This production mode can be enhanced in several extensions of the standard model (SM) such as in its minimal supersymmetric extension (MSSM) at high tan β. We search for Higgs bosons decaying to tau pairs with one tau decaying to a muon and neutrinos and the other to hadrons. The data are found to be consistent with SM expectations, and we set upper limits on the cross section times branching ratio in the Higgs boson mass range from 90 to 320GeV/c2. We interpret our result in the MSSM parameter space, excluding tan β values down to 25 for Higgs boson masses below 170GeV/c2. © 2011 American Physical Society.

## Duality of a Supersymmetric Standard Model without R Parity

Maekawa, Nobuhiro; Sato, Joe
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
Relevância na Pesquisa
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Recently one of the authors proposed a dual theory of a Supersymmetric Standard Model (SSM) in which it is naturally understood that at least one quark (the top quark) should be heavy, i.e., almost the same order as the weak scale, and the supersymmetric Higgs mass parameter µ can naturally be expected to be small. Unfortunately, the model cannot possess Yukawa couplings of the lepton sector. In this paper, we examine a dual theory of a Supersymmetric Standard Model without R parity. In this scenario, we can introduce Yukawa couplings of the lepton sector. In order to induce sufficiently large Yukawa couplings of leptons, we must introduce fairly large R parity breaking terms, which may be observed in the near future.

## Physics beyond the standard model at hera

Cornet, Fernando; Rico, Javier
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
85.86%
This talk is divided in two parts. In the first one we discuss the signals of the Minimal Supersymmetric Standard Model through the production of eq. The second part is devoted to contact terms. The bounds on the mass scale A obtained from atomic parity violation experiments and from LEP are reviewed. Afterwards, we show that the excess of events at high Q-2 observed at HERA could be explained in terms of these contact terms.

## Some Recent Results from the Generic Supersymmetric Standard Model

Kong, Otto C. W.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.96%
The generic supersymmetric standard model is a model built from a supersymmetrized standard model field spectrum the gauge symmetries only. The popular minimal supersymmetric standard model differs from the generic version in having R-parity imposed by hand. We review an efficient formulation of the model and some of the recently obtained interesting phenomenological features. The latter includes R-parity violating contributions to scalar masses that had been largely overlooked and the related contributions to fermion electric dipole moments and $\mu \to e \gamma$.; Comment: 4 pages latex using Rinton-P10x7.cls (included), talk presented at PASCOS 2001

## Higgs bosons in the Standard Model and the Minimal Supersymmetric Standard Model

Quiros, M.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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In these lectures we present a brief review of the Higgs boson sector in the Standard Model'', and its Minimal Supersymmetric Extension, with particular emphasis on the main mechanisms for Higgs production and decay at LEP2 and LHC, and theoretical bounds on the Higgs boson masses. In the Standard Model'' the effective potential can develop a non-standard minimum for values of the field much larger than the weak scale. Comparison of the decay rate to the non-standard minimum at finite (and zero) temperature with the corresponding expansion rate of the Universe allows to identify the region, in the ($M_H$, $M_t$)-plane which can be accomodated by the theory. In the Minimal Supersymmetric Standard Model'', approximate analytical expressions for the Higgs mass spectrum and couplings are worked out. An appropriate treatment of squark decoupling allows to consider large values of the stop mixing parameters and thus fix a reliable upper bound on the mass of the lightest CP-even Higgs boson mass. The discovery of the Higgs boson at LEP2 might put an upper bound (below the Planck scale) on the scale of new physics $\Lambda$ and eventually disentangle between the Standard Model and the Minimal Supersymmetric Standard Model.; Comment: 28 pages...

## Electric Dipole Moments in the Generic Supersymmetric Standard Model

Kong, Otto C. W.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.96%
The generic supersymmetric standard model is a model built from a supersymmetrized standard model field spectrum the gauge symmetries only. The popular minimal supersymmetric standard model differs from the generic version in having R-parity imposed by hand. We review an efficient formulation of the model and some of the recently obtained interesting phenomenological features, focusing on one-loop contributions to fermion electric dipole moments.; Comment: 1+7 pages Revtex 3 figures incoporated; talk at NANP'01

## Bounds on the Higgs mass in the Standard Model and the Minimal Supersymmetric Standard Model

Quirós, M.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.02%
Depending on the Higgs-boson and top-quark masses, $M_H$ and $M_t$, the effective potential of the {\bf Standard Model} can develop a non-standard minimum for values of the field much larger than the weak scale. In those cases the standard minimum becomes metastable and the possibility of decay to the non-standard one arises. Comparison of the decay rate to the non-standard minimum at finite (and zero) temperature with the corresponding expansion rate of the Universe allows to identify the region, in the ($M_H$, $M_t$) plane, where the Higgs field is sitting at the standard electroweak minimum. In the {\bf Minimal Supersymmetric Standard Model}, approximate analytical expressions for the Higgs mass spectrum and couplings are worked out, providing an excellent approximation to the numerical results which include all next-to-leading-log corrections. An appropriate treatment of squark decoupling allows to consider large values of the stop and/or sbottom mixing parameters and thus fix a reliable upper bound on the mass of the lightest CP-even Higgs boson mass. The discovery of the Higgs boson at LEP~2 might put an upper bound (below the Planck scale) on the scale of new physics $\Lambda$ and eventually disentangle between the Standard Model and the Minimal Supersymmetric Standard Model.; Comment: 13 pages...

## Bounds on the Higgs Mass in the Standard Model and Minimal Supersymmetric Standard Model

Quirós, Mariano
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.99%
We present bounds on the Higgs mass in the Standard Model and in the Minimal Supersymmetric Standard Model using the effective potential with next-to-leading logarithms resummed by the renormalization group equations, and physical (pole) masses for the top quark and Higgs boson. In the Standard Model we obtain lower bounds from stability requirements: they depend on the top mass and the cutoff scale. In the Minimal Supersymmetric Standard Model we obtain upper bounds which depend on the top mass and the scale of supersymmetry breaking. A Higgs mass measurement could discriminate, depending on the top mass, between the two models. Higgs discovery at LEP-200 can put an upper bound on the scale of new physics.; Comment: Based on talk given at "Physics from Planck scale to electroweak scale", Warsaw, Poland 21-24 September 1994, 13 pages, latex, 5 postscript figures included in the text by PSFIG.STY appended uuencoded compressed

## The Electroweak Phase Transition in the Minimal Supersymmetric Standard Model

Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.96%
Using dimensional reduction we construct an effective 3D theory of the Minimal Supersymmetric Standard Model at finite temperature. The final effective theory is obtained after three successive stages of integration out of massive particles. We obtain the full 1-loop relation between the couplings of the reduced theory and the underlying 4D couplings and masses. The procedure is also applied to a general two Higgs doublet model and the Next to Minimal Supersymmetric Standard Model. We analyze the effective 3D theory constructed for the MSSM to determine the regions of parameter space for which electroweak baryogenesis is possible. We find that the inclusion of all supersymmetric scalars has the effect of enhancing the strength of the phase transition. The requirement of a very light stop is not necessary for baryogenesis. The phase transition is sufficiently first order if the lightest Higgs mass, $m_{h} ~< 70$ GeV. We note the existence of potentially interesting regions of parameter space for which existing analysis techniques are inadequate to decide the question.; Comment: 38 pages, 12 figures, uses epsf and ruthesis.sty

## Constructing the supersymmetric Standard Model from intersecting D6-branes on the Z_6' orientifold

Bailin, David; Love, Alex
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.03%
Intersecting stacks of supersymmetric fractional branes on the Z_6' orientifold may be used to construct the supersymmetric Standard Model. If $a,b$ are the stacks that generate the SU(3)_{colour} and SU(2)_L gauge particles, then, in order to obtain just the chiral spectrum of the (supersymmetric) Standard Model (with non-zero Yukawa couplings to the Higgs mutiplets),it is necessary that the number of intersections $a \cap b$ of the stacks $a$ and $b$, and the number of intersections $a \cap b'$ of $a$ with the orientifold image $b'$ of $b$ satisfy $(a \cap b,a \cap b')=(2,1)$ or $(1,2)$. It is also necessary that there is no matter in symmetric representations of the gauge group, and not too much matter in antisymmetric representations, on either stack. Fractional branes having all of these properties may be constructed on the Z_6' orientifold. We provide a number of new examples having these properties, some of which may be extended to give the Standard Model spectrum. Specifically, we construct four-stack models with two further stacks, each with just a single brane, which have the matter spectrum of the supersymmetric Standard Model, including a single pair of Higgs doublets, {\em plus} three right-chiral neutrino singlets. Ramond-Ramond tadpole cancellation is achieved by the introduction of background H_3 flux...

## On the Formulation of the Generic Supersymmetric Standard Model (or Supersymmetry without R parity)

Kong, Otto C. W.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.02%
The generic supersymmetric version of the Standard Model would have the minimal list of superfields incorporating the Standard Model particles, and a Lagrangian dictated by the Standard Model gauge symmetries. To be phenomenologically viable, soft supersymmetry breaking terms have to be included. In the most popular version of the supersymmetric Standard Model, an {\it ad hoc} discrete symmetry, called R parity, is added in by hand. While there has been a lot of various kinds of R-parity violation studies in the literature, the complete version of supersymmetry without R parity is not popularly appreciated. In this article, we present a pedagogical review of the formulation of this generic supersymmetric Standard Model and give a detailed discussion on the basic conceptual issues involved. Unfortunately, there are quite some confusing, or even plainly wrong, statements on the issues within the literature of R-parity violations. We aim at clarifying these issues here. We will first discuss our formulation, about which readers are urged to read without bias from previous acquired perspectives on the topic. Based on the formulation, we will then address the various issues . In relation to phenomenology, our review here will not go beyond tree-level mass matrices. But we will give a careful discussion of mass matrices of all the matter fields involved. Useful expressions for perturbative diagonalizations of the mass matrices at the phenomenologically interesting limit of corresponds to small neutrino masses are derived. All these expressions are given in the fully generic setting...

## Renormalization Group Study of the Standard Model and its Extensions: II. the Minimal Supersymmetric Standard Model

Castano, D. J.; Piard, E. J.; Ramond, P.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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In this paper we summarize the minimal supersymmetric standard model as well as the renormalization group equations of its parameters. We proceed to examine the feasability of the model when the breaking of supersymmetry is parametrized by the soft terms suggested by supergravity theories. In such models, the electroweak symmetry is exact at tree level and is broken spontaneously at one loop order. We make the additional assumption that the GUT-inspired relation $m_b=m_\tau$ be valid at the scale where the gauge coupling constants unify, which constrains the value of the top quark mass. For all types of soft breaking terms expected in supergravity theories, we present the results of numerical runs which yield electroweak breaking at the required scale. These yield not only the allowed ranges for the soft supersymmetry breaking parameters, but also the value of the supersymmetric partner' masses. For example in the strict no-scale model, in which global supersymmetry breaking arises solely from soft supersymmetry breaking parameters, but also the value of the supersymmetric partner' masses. For example in the strict no-scale model, in which global supersymmetry breaking arises solely from soft gaugino masses, we find that $M_t$ can be no heavier than $\sim 127$ GeV.; Comment: 41 pages. ReVTeX typeset. 8 figures not included but available (as well as a full postscript version of the paper including the figures) by anonymous FTP at uful07.phys.ufl.edu in the het/UFIFT-HEP-93-18 directory. Report No. UFIFT-HEP-93-18

## Almost the supersymmetric Standard Model from intersecting D6-branes on the Z_6' orientifold

Bailin, David; Love, Alex
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.01%
Intersecting stacks of supersymmetric fractional branes on the Z_6' orientifold may be used to construct the supersymmetric Standard Model. If a,b are the stacks that generate the SU(3)_{colour} and SU(2)_L gauge particles, then, in order to obtain {\em just} the chiral spectrum of the (supersymmetric) Standard Model (with non-zero Yukawa couplings to the Higgs mutiplets), it is necessary that the number of intersections a \cap b of the stacks a and b, and the number of intersections a \cap b' of a with the orientifold image b' of b satisfy (a \cap b,a \cap b')=(2,1) or (1,2). It is also necessary that there is no matter in symmetric representations of the gauge group, and not too much matter in antisymmetric representations, on either stack. Fractional branes having all of these properties may be constructed on the Z_6' orientifold. We construct a (four-stack) model with two further stacks, each with just a single brane, which has precisely the matter spectrum of the supersymmetric Standard Model, including a single pair of Higgs doublets. However, the gauge group is SU(3)_{\rm colour} x SU(2)_L x U(1)_Y x U(1)_H. Only the Higgs doublets are charged with respect to U(1)_H.; Comment: 8 pages, no figures

## The Generic Supersymmetric Standard Model as the Complete Theory of Supersymmetry without R-parity

Kong, Otto C. W.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.97%
The generic supersymmetric standard model is a model built from a supersymmetrized standard model field spectrum the gauge symmetries only. The popular minimal supersymmetric standard model differs from the generic version in having R-parity imposed by hand. We review an efficient formulation of the model in which all the admissible R-parity violating terms are incorporated without bias. The model gives many new interesting R-parity violating phenomenological features only started to be studied recently. Some of our recent results will be discussed, including newly identified 1-loop contributions to neutrino masses and electric dipole moments of neutron and electron. This is related to the largely overlooked R-parity violating contributions to squark and slepton mixings, which we also present in detail.; Comment: 10 pages latex using espcrc2.sty (included) with a latex table and 3 eps- figure files incoporated, typos in a couple of expressions fixed

## The Non-Minimal Supersymmetric Standard Model with $\tan\beta\simeq m_t/m_b$

Ananthanarayan, B.; Pandita, P. N.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66%
We consider the supersymmetric extension of the standard model with an additional singlet $S$, the Non-Minimal Supersymmetric Standard Model (NMSSM), in the limit $\tan\beta \simeq m_t/m_b$. We embed this model in a supergravity framework with universal boundary conditions and analyze the renormalization group improved tree-level potential. We examine the relationship between this model and the minimial supersymmetric standard model (MSSM), and discuss the novel connections between the two when $\tan\beta$ is large. Strong correlations between the free parameters of the nonminimal model are found and the reasons for these discussed. The singlet vacuum expectation value is forced to be large, of the order of $10 TeV$. The radiatively corrected mass of the lightest Higgs boson is found to be $\stackrel{_<}{_\sim} 140 GeV$.; Comment: 22 pages plain LaTeX including 1 Table and 1 Figure

## Higher Order Corrections and Unification in the Minimal Supersymmetric Standard Model: SOFTSUSY3.5.0

Allanach, B. C.; Bednyakov, A.; de Austri, R. Ruiz
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.98%
We explore the effects of three-loop minimal supersymmetric standard model renormalisation group equation terms and some leading two-loopthreshold corrections on gauge and Yukawa unification: each being one loop higher order than current public spectrum calculators. We also explore the effect of the higher order terms (often 2-3 GeV) on the lightest CP even Higgs mass prediction. We illustrate our results in the constrained minimal supersymmetric standard model. Neglecting threshold corrections at the grand unified scale, the discrepancy between the unification scale $\alpha_s$ and the other two unified gauge couplings changes by 0.1$\%$ due to the higher order corrections and the difference between unification scale bottom-tau Yukawa couplings neglecting unification scale threshold corrections changes by up to 1$\%$. The difference between unification scale bottom and top Yukawa couplings changes by a few percent. Differences due to the higher order corrections also give an estimate of the size of theoretical uncertainties in the minimal supersymmetric standard model spectrum. We use these to provide estimates of theoretical uncertainties in predictions of the dark matter relic density (which can be of order one due to its strong dependence on sparticle masses) and the LHC sparticle production cross-section (often around 30$\%$). The additional higher order corrections have been incorporated into SOFTSUSY...

## Beyond the Minimal Supersymmetric Standard Model: from theory to phenomenology

Fuks, Benjamin
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.02%
Thanks to the latest development in the field of Monte Carlo event generators and satellite programs allowing for a straightforward implementation of any beyond the Standard Model theory in those tools, studying the property of any softly-broken supersymmetric theory is become an easy task. We illustrate this statement in the context of two non-minimal supersymmetric theories, namely the Minimal Supersymmetric Standard Model with R-parity violation and the Minimal R-symmetric Supersymmetric Standard Model and choose to probe interaction vertices involving a non-standard color structure and the sector of the top quark. We show how to efficiently implement these theories in the Mathematica package FeynRules and use its interfaces to Monte Carlo tools for phenomenological studies. For the latter, we employ the latest version of the MadGraph program.; Comment: 39 pages, 5 figures, 7 tables; to appear in Mod. Phys. Lett. A

## Searches for direct pair production of supersymmetric top and supersymmetric bottom quarks in pp̅ collisions at √s=1.96  TeV

Aaltonen, T.; Vila, Iván; Vilar, Rocío; Rodrigo, Teresa; Cabrera, Susana; Chuang, S. H.; Ruiz Jimeno, Alberto; Gómez, G.; Cuenca Almenar, Cristóbal; Cuevas, Javier; Palencia, Enrique; Piedra, Jonatan; Scodellaro, Luca; Casal, Bruno
Fonte: American Physical Society Publicador: American Physical Society
Tipo: Artículo Formato: 2373 bytes; text/plain
ENG
Relevância na Pesquisa
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12 páginas, 5 figuras, 4 tablas.-- PACS nrs.: 12.60.Jv, 13.85.Rm, 14.80.Ly.-- CDF Collaboration: et al.; We search for direct pair production of supersymmetric top quarks and supersymmetric bottom quarks in proton-antiproton collisions at root s=1.96 TeV, using 295 pb(-1) of data recorded by the Collider Detector at Fermilab (CDF II) experiment. The supersymmetric top (supersymmetric bottom) quarks are selected by reconstructing their decay into a charm (bottom) quark and a neutralino, which is assumed to be the lightest supersymmetric particle. The signature of such processes is two energetic heavy-flavor jets and missing transverse energy. The number of events that pass our selection for each search process is consistent with the expected standard model background. By comparing our results to the theoretical production cross sections of the supersymmetric top and supersymmetric bottom quarks in the minimal supersymmetric standard model, we exclude, at a 95% confidence level in the frame of that model, a supersymmetric top quark mass up to 132 GeV/c^2 for a neutralino mass of 48 GeV/c^2, and a supersymmetric bottom quark mass up to 193 GeV/c^2 for a neutralino mass of 40 GeV/c^2.; This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education...

## Measuring supersymmetric particle masses at the LHC in scenarios with baryon number R-parity violating couplings.

Allanach, B. C.; Barr, Alan; Drage, L.; Lester, Christopher G.; Morgan, D.; Parker, Michael A.; Webber, Bryan R.; Richardson, P.
Fonte: HEP, Cavendish Laboratory, University of Cambridge Publicador: HEP, Cavendish Laboratory, University of Cambridge
Tipo: Article; not applicable
EN
Relevância na Pesquisa
75.85%
The measurement of sparticle masses in the Minimal Supersymmetric Standard Model at the LHC is analysed, in the scenario where the lightest neutralino, the ??01 , decays into three quarks. Such decays, occurring through the baryon-number violating coupling ??? ijk, pose a severe challenge to the capability of the LHC detectors since the final state has no missing energy signature and a high jet multiplicity. We focus on the case ??? 212 6= 0 which is the most difficult experimentally. The proposed method is valid over a wide range of SUGRA parameter space with ??? 212 ? 10?5?0.1. Simulations are performed of the ATLAS detector at the Large Hadron Collider. Using the ??01 from the decay chain ?qL ? ??02 q ? ?lR?q ? ??01 ??q, we show that the ??01 and ??02 masses can be measured by 3-jet and 3-jet + lepton pair invariant mass combinations. At the SUGRA point m0 = 100 GeV, m1/2 = 300 GeV, A0 = 300 GeV, tan ? = 10, ? > 0 and with ??? 212 = 0.005, we achieve statistical (systematic) errors of 3 (3), 3 (3), 0.3 (4) and 5 (12) GeV respectively for the masses of the ??01 , ??02 , ?lR and ?qL, with an integrated luminosity of 30 fb?1.

## Higher order corrections and unification in the minimal supersymmetric standard model: SOFTSUSY3.5

Allanach, B. C.; Bednyakov, A.; Ruiz de Austri, R.