Results for "Stefan Pokorski"

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The Role of the Anomalous U(1)_A for the Solution of the Doublet-Triplet Splitting ProblemOct 21 1996The anomalous U(1)_A symmetry provides a generic method of getting accidental symmetries. Therefore, it can play a crucial role in solving the doublet-triplet splitting and the \mu-problems via the `pseudo-Goldstone' mechanism: U(1)_A can naturally uncorrelate ... More
Top Quark Mass and SupersymmetryJul 12 1994We summarize the expectations for the top quark mass in supersymmetric models and discuss the potential implications of its value measured by the CDF group in Fermilab.
Phenomenological guide to physics beyond the Standard ModelFeb 14 2005Various aspects of physics beyond the Standard Model are discussed from the perspective of the fantastic phenomenological success of the Standard Model, its simplicity and predictive power
Status of the Minimal Supersymmetric Standard ModelOct 04 1995Recent results in study of the Minimal Supersymmetric Standard Model as the effective low energy theory give important hints for experimental search for supersymmetry. Also, in the bottom-up approach to explore weak scale - GUT scale connection, they ... More
Can the differences in the determinations of $V_{ub}$ and $V_{cb}$ be explained by New Physics?Jul 04 2014Dec 19 2014The precise determination of the CKM elements $V_{cb}$ and $V_{ub}$ is crucial for any new physics analysis in the flavour sector. Their values can be determined from several tree-level decays: $V_{cb}$ can be extracted from $B\to D\ell\nu$ and $B\to ... More
Three Neutrino Oscillations in MatterJan 31 2018Jul 12 2018Following similar approaches in the past, the Schrodinger equation for three neutrino propagation in matter of constant density is solved analytically by two successive diagonalizations of 2x2 matrices. The final result for the oscillation probabilities ... More
Three Neutrino Oscillations in Uniform MatterDec 03 2018Following similar approaches in the past, the Schrodinger equation for three neutrino propagation in matter of constant density is solved analytically by two successive diagonalizations of 2x2 matrices. The final result for the oscillation probabilities ... More
Naturally Light Higgs Doublet in the Spinor Representation of SUSY SO(10)Jan 29 1996Within the supersymmetric SO(10) GUT we explore the possibility of the light Higgs doublet being a member of the 16-dimensional spinorial representation. This fact is ultimately related with the assumption that the light matter (at least partially) resides ... More
Lepton-flavour violating $B$ decays in generic $Z^\prime$ modelsApr 29 2015Sep 24 2015LHCb has reported deviations from the Standard Model in $b\to s\mu^+\mu^-$ transitions for which a new neutral gauge boson is a prime candidate for an explanation. As this gauge boson has to couple in a flavour non-universal way to muons and electrons ... More
Physics of Extra Dimensions as IR Limit of Four-Dimensional TheoriesJul 06 2001I discuss the recent work done in collaboration with Chris Hill, Jing Wang and Hsin-Chia Cheng. We construct four-dimensional renormalizable gauge theories which, in their infrared limit, generate the dynamics of gauge interactions in flat extra dimensions. ... More
Slepton Flavour Mixing and Neutrino MassesDec 01 1999It is pointed out that important contribution to neutrino masses and mixing can come from flavour violating slepton exchange. For low and intermediate $\tan\beta$ such effects can dominate over the usual tau Yukawa coupling effects included in the renormalization ... More
Five-Dimensional Aspects of M-Theory Dynamics and Supersymmetry BreakingMay 19 1998Oct 30 1998We discuss the reduction of the eleven-dimensional M-theory effective Lagrangian, considering first compactification from eleven to five dimensions on a Calabi-Yau manifold, followed by reduction to four dimensions on an S_1/Z_2 line segment at a larger ... More
Gauge Invariant Effective Lagrangian for Kaluza-Klein ModesApr 04 2001Apr 05 2001We construct a manifestly gauge invariant Lagrangian in 3+1 dimensions for N Kaluza-Klein modes of an SU(m) gauge theory in the bulk. For example, if the bulk is 4+1, the effective theory is \Pi_{i=1}^{N+1} SU(m)_i with N chiral (\bar{m},m) fields connecting ... More
Spin--1/2 Particle in Gravitational Field of a Rotating BodyMay 12 1995Effective Lagrangian describing gravitational source spin-particle spin interactions is given. Cosmological and astrophysical consequences of such interaction are examined. Although stronger than expected, the spin-spin interactions do not change any ... More
Finite Supersymmetric Threshold Corrections to CKM Matrix Elements in the Large $tanβ$ RegimeApr 22 1995We evaluate the finite 1-loop threshold corrections, proportional to $tan\beta$, to the down quark mass matrix. These result in corrections to down quark masses and to Cabibbo-Kobayashi-Maskawa [CKM] matrix elements. The corrections to CKM matrix elements ... More
Supersymmetrizing Branes with Bulk in Five-Dimensional SupergravityApr 12 2000May 17 2000We supersymmetrize a class of moduli dependent potentials living on branes with the help of additional bulk terms in 5d N=2 supergravity. The space of Poincare invariant vacuum solutions includes the Randall-Sundrum solution and the $M$-theoretical solution. ... More
Deconstructed U(1) and Supersymmetry BreakingMar 18 2003We discuss supersymmetry breaking induced by simultaneous presence of a Wilson-line type superpotential and boundary-localized Fayet-Iliopoulos terms in a four dimensional theory based on deconstruction of five-dimensional abelian gauge theories on orbifolds. ... More
Modelling strong interactions and longitudinally polarized vector boson scatteringMay 31 2007Jun 19 2007We study scattering of the electroweak gauge bosons in 5D warped models. Within two different models we determine the precise manner in which the Higgs boson and the vector resonances ensure the unitarity of longitudinal vector boson scattering. We identify ... More
New Regions in the NMSSM with a 125 GeV HiggsApr 19 2013Jun 10 2013It is pointed out that mixing effects in the CP-even scalar sector of the NMSSM can give 6-8 GeV correction to the SM-like Higgs mass in moderate or large $\tan\beta$ regions with a small value of the singlet-higgs-higgs superfields coupling $\lambda\sim\mathcal{O}(0.1)$. ... More
Beyond MFV in family symmetry theories of fermion massesJun 11 2010Minimal Flavour Violation (MFV) postulates that the only source of flavour changing neutral currents and CP violation, as in the Standard Model, is the CKM matrix. However it does not address the origin of fermion masses and mixing and models that do ... More
Unification in models with replicated gauge groupsSep 27 2001We examine unification of gauge couplings in four dimensional renormalizable gauge theories inspired by the latticized (deconstructed) SM or MSSM in five dimensions. The models are based on replicated gauge groups, spontaneously broken to the diagonal ... More
Four-Dimensional Supergravities from Five-Dimensional Brane WorldsFeb 21 2001Mar 11 2001We give the explicit form of the four dimensional effective supergravity action, which describes low energy physics of the Randall-Sundrum model with moduli fields in the bulk and charged chiral matter living on the branes. The relation between 5d and ... More
Flavour violation in general supergravityFeb 08 2005We reappraise the flavour changing neutral currents (FCNC) problem in string--derived supergravity models. We overview and classify possible sources of flavour violation and find that the problem often does not arise in classes of models which generate ... More
Moduli stabilization and uplifting with dynamically generated F-termsOct 27 2006Nov 28 2006We use the F-term dynamical supersymmetry breaking models with metastable vacua in order to uplift the vacuum energy in the KKLT moduli stabilization scenario. The main advantage compared to earlier proposals is the manifest supersymmetric treatment and ... More
Axions in a highly protected gauge symmetry modelApr 03 2018Dec 29 2018We study QCD axion or cosmological axion-like particles (ALPs) in a model inspired by the recent interest in 4-dimensional clockwork models, with the global symmetry being accidentally enforced by a gauge abelian quiver with scalar bifundamental fields. ... More
Viable $t$-$b$-$τ$ Yukawa Unification in SUSY SO(10)Oct 18 1995The supersymmetric SO(10) GUT with $t$--$b$--$\tau$ Yukawa coupling unification has problems with correct electroweak symmetry breaking, experimental constraints (especially $b\rightarrow s\gamma$) and neutralino abundance, if the scalar masses are universal ... More
Five-Dimensional Gauged Supergravities with Universal Hypermultiplet and Warped Brane WorldsSep 21 2000We present five dimensional gauged supergravity with universal hypermultiplet on M_4 \times S^1 / Z_2 coupled supersymmetrically to three-branes located at the fixed points. The construction is extended to the smooth picture with auxiliary singlet and ... More
Twin SUSYApr 07 2006Apr 22 2006We construct an extension of the MSSM in which superpartners can naturally be heavier than the electroweak scale. This ``little hierarchy'' of scales is stable because the Higgs arises as a pseudo-Nambu-Goldstone boson in the breaking of an accidental ... More
Stabilized Singlets in Supergravity as a Source of the mu-parameterMar 11 1998Within the context of supergravity-coupled supersymmetry, fields which are gauge and global singlets are usually considered anathema. Their vacuum expectation values are shifted by quadratically divergent tadpole diagrams which are cutoff at the Planck ... More
Yukawa unification in SO(10) with light sparticle spectrumJul 14 2011We investigate supersymmetric SO(10) GUT model with \mu<0. The requirements of top-bottom-tau Yukawa unification, correct radiative electroweak symmetry breaking and agreement with the present experimental data may be met when the soft masses of scalars ... More
Beyond the Standard Embedding in M-Theory on S^1/Z_2Jul 26 1998Sep 18 1998In this paper we discuss compactifications of M-theory to four dimensions on X \times S^1/Z_2, in which nonstandard embeddings in the E_8 \times E_8 vacuum gauge bundle are considered. At the level of the effective field theory description of Horava and ... More
Gravity in Gauge MediationAug 04 2008Aug 18 2008We investigate O'Raifeartaigh-type models for F-term supersymmetry breaking in gauge mediation scenarios in the presence of gravity. It is pointed out that the vacuum structure of those models is such that in metastable vacua gravity mediation contribution ... More
Experimental signatures of a light singlet-like scalar in NMSSMJun 05 2014NMSSM with a light singlet-like scalar and strongly suppressed couplings to $b$ and $\tau$ is investigated. It is shown that in such a scenario the singlet-like scalar to diphoton signal can be larger than for the SM Higgs for a wide range of masses between ... More
125 GeV Higgs and enhanced diphoton signal of a light singlet-like scalar in NMSSMOct 16 2013NMSSM with a light singlet-like scalar and strongly suppressed couplings to $b$ and $\tau$ is investigated. It is shown that in such a scenario the singlet-like scalar to diphoton signal can be larger than for the SM Higgs for a wide range of masses between ... More
Light staus and enhanced Higgs diphoton rate with non-universal gaugino masses and SO(10) Yukawa unificationJul 30 2013Oct 17 2013It is shown that substantially enhanced Higgs to diphoton rate induced by light staus with large left-right mixing in MSSM requires at the GUT scale non-universal gaugino masses with bino and/or wino lighter than gluino. The possibility of such enhancement ... More
Supersymmetry and FCNC effectsMar 27 1997Nov 19 1997We consider Flavour Changing Neutral Current processes in the framework of the supersymmetric extension of the Standard Model. FCNC constraints on the structure of sfermion mass matrices are reviewed. Furthermore, we analyze supersymmetric contributions ... More
Proton decay testing low energy SUSYJul 20 2017We show that gauge coupling unification in SUSY models can make a non-trivial interconnection between collider and proton decay experiments. Under the assumption of precise gauge coupling unification in the MSSM, the low energy SUSY spectrum and the unification ... More
Supersymmetry at the electroweak scaleJul 15 1996The simplest interpretation of the global success of the Standard Model is that new physics decouples well above the electroweak scale. Supersymmetric extension of the Standard Model offers the possibility of light chargino and the right-handed stop (with ... More
Precision tests of the MSSMMay 15 1995We present the results of a first global fit to the electroweak observables in the MSSM. The best fit selects either very low or very large values of ~$\tan\beta$ ~and, correspondingly, chargino (higgsino--like) and stop or the ~$CP-$odd Higgs boson are ... More
Tools for Deconstructing Gauge Theories in AdS5May 16 2006Jun 09 2006We employ analytical methods to study deconstruction of 5D gauge theories in the AdS5 background. We demonstrate that using the so-called q-Bessel functions allows a quantitative analysis of the deconstructed setup. Our study clarifies the relation of ... More
A new approach to gauge coupling unification and proton decayFeb 16 2019A novel analytical formalism is proposed, linking the supersymmetric and GUT spectra in any GUT model in which the three gauge couplings unify. In each specific GUT model, one can then fully explore the interplay between the pattern of supersymmetry breaking ... More
Supergravity and Supersymmetry Breaking in Four and Five DimensionsJun 18 1999We discuss supersymmetry breaking in the field-theoretical limit of the strongly-coupled heterotic string compactified on a Calabi-Yau manifold, from the different perspectives of four and five dimensions. The former applies to light degrees of freedom ... More
The effective supergravity of Little String TheoryOct 16 2017In this work we present the minimal supersymmetric extension of the five-dimensional dilaton-gravity theory that captures the main properties of the holographic dual of little string theory. It is described by a particular gauging of $\mathcal{N}=2$ supergravity ... More
Interpreting 750 GeV Diphoton Excess in Plain NMSSMMar 07 2016Jul 04 2016NMSSM has enough ingredients to explain the diphoton excess at 750 GeV: singlet-like (pseudo) scalar ($a$) $s$ and higgsinos as heavy vector-like fermions. We consider the production of the 750 GeV singlet-like pseudo scalar a from a decay of the doublet-like ... More
Linking Natural Supersymmetry to Flavour PhysicsAug 05 2013Feb 07 2014With the aim of linking natural supersymmetry to flavour physics, a model is proposed based on a family symmetry G \times U(1), where G is a discrete nonabelian subgroup of SU(2), with both F-term and (abelian) D-term supersymmetry breaking. A good fit ... More
Deconstructing 5D supersymmetric U(1) gauge theories on orbifoldsDec 17 2002Jun 11 2003We investigate deconstruction of five dimensional supersymmetric abelian gauge theories compactified on $S_1/Z_2$, with various sets of bulk and matter multiplets. The problem of anomalies, chirality and stability in the deconstructed theories is discussed. ... More
Resolving charm and bottom quark masses in precision Higgs boson analysesSep 14 2015Masses of the charm and bottom quarks are important inputs to precision calculations of Higgs boson observables, such as its partial widths and branching fractions. They constitute a major source of theory uncertainties that needs to be better understood ... More
Detecting underabundant neutralinosJun 23 2015Oct 10 2015The electroweak sector may play a crucial role in discovering supersymmetry. We systematically investigate the patterns of the MSSM-like electroweakinos, when the neutralino relic abundance $\Omega_\chi h^2\leq 0.12$, that is, also admitting for multi-component ... More
Double protection of the Higgs potentialSep 27 2005Oct 05 2005A mechanism of double protection of the Higgs potential, by supersymmetry and by a global symmetry, is investigated in a class of supersymmetric models with the SU(3)xSU(3)xU(1) gauge symmetry. In such models the electroweak symmetry can be broken with ... More
Extra U(1) as natural source of a monochromatic gamma ray lineMay 07 2012Oct 17 2012Extensions of the Standard Model with an extra U'(1) abelian group generically generate terms coming from loops of heavy fermions, leading to three gauge boson couplings, in particular Z'Z gamma. We show that WMAP data constrains the gauge coupling of ... More
The Messenger Sector of SUSY Flavour Models and Radiative Breaking of Flavour UniversalityMar 07 2012May 11 2012The flavour messenger sectors and their impact on the soft SUSY breaking terms are investigated in SUSY flavour models. In the case when the flavour scale M is below the SUSY breaking mediation scale M_S, the universality of soft terms, even if assumed ... More
The Standard Model in the Latticized BulkApr 20 2001We construct the manifestly gauge invariant effective Lagrangian in 3+1 dimensions describing the Standard Model in 4+1 dimensions, following the transverse lattice technique. We incorporate split generation fermions and we explore naturalness for two ... More
SUSY Meets Her TwinNov 25 2016We investigate the general structure of mirror symmetry breaking in the Twin Higgs scenario. We show, using the IR effective theory, that a significant gain in fine tuning can be achieved if the symmetry is broken hardly. We emphasize that weakly coupled ... More
Inverted sfermion mass hierarchy and the Higgs boson mass in the MSSMMay 08 2012Aug 09 2012It is shown that MSSM with first two generations of squarks and sleptons much heavier than the third one naturally predicts the maximal stop mixing as a consequence of the RG evolution, with vanishing (or small) trilinear coupling at the high scale. The ... More
Reheating Temperature and Gauge Mediation Models of Supersymmetry BreakingAug 18 2009Sep 17 2009For supersymmetric theories with gravitino dark matter, the maximal reheating temperature consistent with big bang nucleosynthesis bounds arises when the physical gaugino masses are degenerate. We consider the cases of a stau or sneutrino next-to-lightest ... More
The role of low-energy observables in precision Higgs analysisJan 12 2015Apr 01 2015A conventional approach to precision calculations of Higgs boson observables uses quark masses $m_c$ and $m_b$ as inputs. However, quark masses are single numbers that hide a variety of low-energy data from which they are extracted, and also hide the ... More
Real Scalar Dark Matter: Relativistic TreatmentJun 18 2019Jun 20 2019A stable real scalar provides one of the simplest possibilities to account for dark matter. We consider the regime where its coupling to the Standard Model fields is negligibly small. Due to self-coupling, the scalar field can reach thermal or at least ... More
Gravitino vs Neutralino LSP at the LHCMay 14 2019Using the latest LHC data, we analyse and compare the lower limits on the masses of gluinos and the lightest stop in two natural supersymmetric motivated scenarios: one with a neutralino being the lightest supersymmetric particle (LSP) and the other one ... More
Higgs doublet as a Goldstone boson in perturbative extensions of the Standard ModelMay 14 2008Nov 07 2008We investigate the idea of the Higgs doublet as a pseudo-Goldstone boson in perturbative extensions of the Standard Model, motivated by the desire to ameliorate its hierarchy problem without conflict with the electroweak precision data. Two realistic ... More
Evading Direct Dark Matter Detection in Higgs Portal ModelsNov 29 2016Many models of Higgs portal Dark Matter (DM) find themselves under pressure from increasingly tight direct detection constraints. In the framework of gauge field DM, we study how such bounds can be relaxed while retaining the thermal WIMP paradigm. When ... More
If no Higgs then what?Aug 04 2011Nov 07 2011In the absence of a Higgs boson, the perturbative description of the Standard Model ceases to make sense above a TeV. Heavy spin-1 fields coupled to W and Z bosons can extend the validity of the theory up to higher scales. We carefully identify regions ... More
Real Scalar Dark Matter: Relativistic TreatmentJun 18 2019A stable real scalar provides one of the simplest possibilities to account for dark matter. We consider the regime where its coupling to the Standard Model fields is negligibly small. Due to self-coupling, the scalar field can reach thermal or at least ... More
FCNC Effects in a Minimal Theory of Fermion MassesMay 18 2011As a minimal theory of fermion masses we extend the SM by heavy vectorlike fermions, with flavor-anarchical Yukawa couplings, that mix with chiral fermions such that small SM Yukawa couplings arise from small mixing angles. This model can be regarded ... More
Flavour in supersymmetry: horizontal symmetries or wave function renormalisationJul 29 2010We compare theoretical and experimental predictions of two main classes of models addressing fermion mass hierarchies and flavour changing neutral currents (FCNC) effects in supersymmetry: Froggatt-Nielsen (FN) U(1) gauged flavour models and Nelson-Strassler/extra ... More
Electroweak symmetry breaking in supersymmetric models with heavy scalar superpartnersJul 21 2004We propose a novel mechanism of electroweak symmetry breaking in supersymmetric models, as the one recently discussed by Birkedal, Chacko and Gaillard, in which the Standard Model Higgs doublet is a pseudo-Goldstone boson of some global symmetry. The ... More
Universal Constraints on Low-Energy Flavour ModelsApr 05 2012Jul 22 2015It is pointed out that in a general class of flavour models one can identify certain universally present FCNC operators, induced by the exchange of heavy flavour messengers. Their coefficients depend on the rotation angles that connect flavour and fermion ... More
Custodial supersymmetry in non-supersymmetric quiver theoriesApr 23 2002May 07 2002We consider non-supersymmetric quiver theories obtained by orbifolding the N=4 supersymmetric U(K) gauge theory by a discrete Z_\Gamma group embedded in the SU(4) R-symmetry group. We explicitly find that in such theories there are no one-loop quadratic ... More
Cosmological Fine Tuning, Supersymmetry, and the Gauge Heirarchy ProblemNov 09 1998We study the extent to which the cosmological fine-tuning problem - why the relic density of neutralino cold dark matter particles $\chi$ is similar to that of baryons - is related to the fine-tuning aspect of the gauge hierarchy problem - how one arranges ... More
Gravitino Dark Matter and general neutralino NLSPAug 24 2009We study the scenario of gravitino DM with a general neutralino NLSP in a model independent way. We consider all neutralino decay channels and compare them with the most recent BBN constraints. We check how those bounds are relaxed for a Higgsino or a ... More
Upper bounds on sparticle masses from muon g-2 and the Higgs mass and the complementarity of future collidersNov 05 2014Mar 17 2015Supersymmetric (SUSY) explanation of the discrepancy between the measurement of $(g-2)_\mu$ and its SM prediction puts strong upper bounds on the chargino and smuon masses. At the same time, lower experimental limits on the chargino and smuon masses, ... More
A new approach to gauge coupling unification and proton decayFeb 16 2019May 07 2019An analytical formalism, including RG running at two loop order, is used to link the supersymmetric and GUT spectra in any GUT model in which the three gauge couplings unify. In each specific GUT model, one can then fully explore the interplay between ... More
ALEPH Four-Jet Excess, $R_b$ and $R-$Parity ViolationJun 23 1996Jun 24 1996We review briefly the indications for some relatively light superpartners based on the ~$R_b$ ~anomaly and discuss the dependence of the potential increase in $R_b$ on the assumption about ~$R-$parity (non)conservation. We point out that the exotic 4-jet ... More
$\sin^2θ_W(M_Z)$ ~in the MSSM and Unification of CouplingsNov 07 1994We calculate ~$\sin^2\theta(M_Z)$ ~in the MSSM in terms of ~ $\alpha_{EM}$, ~$G_F$, ~$m_t$, ~$\tan\beta$ ~and SUSY mass parameters with the same accuracy as the present calculations of ~$\sin^2\theta(M_Z)$ ~in the SM. We compare the results with the standard ... More
Constraints on the Minimal SUSY SO(10) Model from Cosmology and the $b\to s γ$ DecayDec 28 1994Dec 29 1994It is shown that the minimal supersymmetric SO(10) model with electroweak radiative breaking and universal soft mass terms at the GUT scale is strongly disfavoured by the combination of constraints from the $b\to s \gamma$ decay and the condition $\Omega ... More
$τ- μ- e$ Universality in $τ$ Decays and Constraints on the Slepton MassesMay 13 1994The leptonic $\tau$ decays are calculated at the 1-loop level in the Minimal Supersymmetric Standard Model. The deviation from the $\tau - \mu - e$ universality is studied as a function of the supersymmetric parameters and discussed in the context of ... More
Complete On-Shell Renormalization Scheme for the Minimal Supersymmetric Higgs SectorMar 26 1993Systematic on-shell renormalization programme is carried out for the Higgs and gauge boson sectors of the Minimal Supersymmetric Standard Model. Complete 1-loop results for the 2- and 3-point Green's functions are explicitly given. The Higgs boson masses ... More
Fixed points in the evolution of neutrino mixingsOct 05 1999Nov 12 1999We derive the renormalization group equations for the neutrino masses and mixing angles in explicit form and discuss the possible classes of their solutions. We identify fixed points in the equations for mixing angles, which can be reached during the ... More
Study of the 125 GeV Standard Model Higgs Boson Partial Widths and Branching FractionsNov 26 2013Mar 23 2014The discovery of the Higgs boson, with mass known to better than the percent level, enables for the first time precision Higgs boson analyses. Toward this goal, we define an expansion formalism of the Higgs boson partial widths and branching fractions ... More
Multicomponent Dark Matter from Gauge SymmetryNov 01 2016The composition of Dark Matter (DM) remains an important open question. The current data do not distinguish between single- and multi-component DM, while in theory constructions it is often assumed that DM is composed of a single field. In this work, ... More
Same-sign WW scattering at the LHC: can we discover BSM effects before discovering new states?Feb 07 2018It is possible that measurements of vector boson scattering (VBS) at the LHC will reveal disagreement with Standard Model predictions, but no new particles will be observed directly. The task is then to learn as much as possible about the new physics ... More
Multicomponent Dark Matter from Gauge SymmetryNov 01 2016Nov 11 2016The composition of Dark Matter (DM) remains an important open question. The current data do not distinguish between single- and multi-component DM, while in theory constructions it is often assumed that DM is composed of a single field. In this work, ... More
Supersymmetric mass spectra for gravitino dark matter with a high reheating temperatureSep 20 2010Supersymmetric theories with gravitino dark matter generally do not allow the high reheating temperature required by thermal leptogenesis without running afoul of relic abundance or big bang nucleosynthesis constraints. We report on a successful search ... More
Patterns of Lepton-Flavour Violation Motivated by Decoupling and Sneutrino InflationMar 16 2004May 11 2004We present predictions for flavour-violating charged-lepton decays induced by the seesaw mechanism implemented within the constrained minimal supersymmetric standard model (CMSSM) with universal input soft supersymmetry breaking terms. We assume that ... More
Same-sign WW scattering at the LHC: can we discover BSM effects before discovering new states?Feb 07 2018Jun 07 2018It is possible that measurements of vector boson scattering (VBS) at the LHC will reveal disagreement with Standard Model predictions, but no new particles will be observed directly. The task is then to learn as much as possible about the new physics ... More
Lepton flavour violation in the MSSM: exact diagonalization vs mass expansionFeb 19 2018May 14 2018The forthcoming precision data on lepton flavour violating decays require precise and efficient calculations in New Physics models. In this article lepton flavour violating processes within the Minimal Supersymmetric Standard Model (MSSM) are calculated ... More
Electroweak interactions -- theoryNov 27 1996In the first part of this talk there is given a very brief review of the status of the Standard Model (SM). In the second part I discuss electroweak interactions and physics beyond the SM.
Status of low energy supersymmetryJan 27 1999Feb 05 1999We review: 1) constraints on low energy supersymmetry from the search for Higgs boson and from precision data, 2) dependence of coupling unification on the superpartner spectrum, 3) naturalness and fine tuning in the minimal and non-minimal scenarios. ... More
What is the mass of the lightest supersymmetric Higgs boson?Feb 27 1997After reviewing briefly the upper bounds on the mass of the lightest Higgs boson in the most general unconstrained minimal supersymmetric extension of the Standard Model, we discuss various arguments which reduce the parameter space of the model and give ... More
Electroweak Symmetry Breaking with Non-Universal Scalar Soft Terms and Large $\tanβ$ SolutionsJul 29 1994We discuss radiative electroweak symmetry breaking with non-universal scalar masses at the GUT scale. Large $\tan\beta$ solutions are investigated in detail and it is shown that qualitatively new (as compared to the universal case) solutions exist, with ... More
Bottom-Up Approach to Uniefied Supergravity ModelsMar 17 1993A new approach is proposed to phenomenological study of a generic unified supergravity model, which reduces to the minimal supersymmetric standard model. The model is effectively parametrized in terms of five low energy observables. In consequence, it ... More
Weak Limit of the 3-State Quantum Walk on the LineApr 04 2014May 21 2014We revisit the one dimensional discrete time quantum walk with 3 states and the Grover coin. We derive analytic expressions for observed the localization, an long time approximation for the probability density function (PDF). We also connect the time ... More
Streaming KernelizationMay 06 2014Kernelization is a formalization of preprocessing for combinatorially hard problems. We modify the standard definition for kernelization, which allows any polynomial-time algorithm for the preprocessing, by requiring instead that the preprocessing runs ... More
On the commutability of homogenization and linearization in finite elasticityNov 16 2010May 16 2011We study non-convex elastic energy functionals associated to (spatially) periodic, frame indifferent energy densities with a single non-degenerate energy well at SO(n). Under the assumption that the energy density admits a quadratic Taylor expansion at ... More
Reliability of regulatory networks and its evolutionMay 27 2008The problem of reliability of the dynamics in biological regulatory networks is studied in the framework of a generalized Boolean network model with continuous timing and noise. Using well-known artificial genetic networks such as the repressilator, we ... More
Reliability of genetic networks is evolvableJul 10 2007Control of the living cell functions with remarkable reliability despite the stochastic nature of the underlying molecular networks -- a property presumably optimized by biological evolution. We here ask to what extent the property of a stochastic dynamical ... More
On Semigroups of Two-Dimensional Upper-Triangular Integer MatricesMay 13 2019We analyze algorithmic problems in finitely generated semigroups of two-dimensional upper-triangular integer matrices. These semigroup problems are tightly connected with problems about compositions of affine functions over one variable. Building on a ... More
The H-Covariant Strong Picard GroupoidSep 08 2004Apr 25 2005The notion of H-covariant strong Morita equivalence is introduced for *-algebras over C = R(i) with an ordered ring R which are equipped with a *-action of a Hopf *-algebra H. This defines a corresponding H-covariant strong Picard groupoid which encodes ... More
A shortcut to (sun)flowers: Kernels in logarithmic space or linear timeApr 30 2015We investigate whether kernelization results can be obtained if we restrict kernelization algorithms to run in logarithmic space. This restriction for kernelization is motivated by the question of what results are attainable for preprocessing via simple ... More
Finite-Size Corrections for Ground States of Edwards-Anderson Spin GlassesOct 28 2011May 30 2012Extensive computations of ground state energies of the Edwards-Anderson spin glass on bond-diluted, hypercubic lattices are conducted in dimensions d=3,..,7. Results are presented for bond-densities exactly at the percolation threshold, p=p_c, and deep ... More
Superstability of the yeast cell cycle dynamics: Ensuring causality in the presence of biochemical stochasticityMay 05 2006Gene regulatory dynamics is governed by molecular processes and therefore exhibits an inherent stochasticity. However, for the survival of an organism it is a strict necessity that this intrinsic noise does not prevent robust functioning of the system. ... More