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Low Q^2 Weak Mixing Angle Measurements and Rare Higgs Decays
http://cds.cern.ch/record/2030725
A weighted average weak mixing angle theta_W derived from relatively low Q^2 experiments is compared with the Standard Model prediction obtained from precision measurements. The approximate 1.8 sigma discrepancy is fit with an intermediate mass (~ 10-35 GeV) "dark" Z boson Z_d, corresponding to a U(1)_d gauge symmetry of hidden dark matter, which couples to our world via kinetic and Z-Z_d mass mixing. Constraints on such a scenario are obtained from precision electroweak bounds and searches for the rare Higgs decays H -> Z Z_d -> 4 charged leptons at the LHC. The sensitivity of future anticipated low Q^2 measurements of sin^2 theta_W(Q^2) to intermediate mass Z_d is also illustrated. This dark Z scenario can provide interesting concomitant signals in low energy parity violating measurements and rare Higgs decays at the LHC, over the next few years.Davoudiasl, HoomanLee, Hye-SungMarciano, William JFri, 03 Jul 2015 05:52:45 GMT01 Jul 2015arXiv:1507.00352http://cds.cern.ch/record/2030725The PDF4LHC report on PDFs and LHC data: Results from Run I and preparation for Run II
http://cds.cern.ch/record/2030721
The accurate determination of the Parton Distribution Functions (PDFs) of the proton is an essential ingredient of the Large Hadron Collider (LHC) program. PDF uncertainties impact a wide range of processes, from Higgs boson characterisation and precision Standard Model measurements to New Physics searches. A major recent development in modern PDF analyses has been to exploit the wealth of new information contained in precision measurements from the LHC Run I, as well as progress in tools and methods to include these data in PDF fits. In this report we summarise the information that PDF-sensitive measurements at the LHC have provided so far, and review the prospects for further constraining PDFs with data from the recently started Run II. This document aims to provide useful input to the LHC collaborations to prioritise their PDF-sensitive measurements at Run II, as well as a comprehensive reference for the PDF-fitting collaborations.Rojo, JuanAccardi, AlbertoBall, Richard DCooper-Sarkar, Amandade Roeck, AlbertFarry, StephenFerrando, JamesForte, StefanoGao, JunHarland-Lang, LucianHuston, JoeyGlazov, AlexanderGouzevitch, MaximeGwenlan, ClaireLipka, KaterinaLisovyi, MykhailoMangano, MichelangeloNadolsky, PavelPerrozzi, LucaPlacakyte, RingaileRadescu, VoicaSalam, Gavin PThorne, RobertFri, 03 Jul 2015 05:51:08 GMT02 Jul 2015arXiv:1507.00556http://cds.cern.ch/record/2030721Color-Kinematics Duality for QCD Amplitudes
http://cds.cern.ch/record/2030454
We show that color-kinematics duality is present in tree-level amplitudes of quantum chromodynamics with massive flavored quarks. Starting with the color structure of QCD, we work out a new color decomposition for n-point tree amplitudes in a reduced basis of primitive amplitudes. These primitives, with k quark-antiquark pairs and (n-2k) gluons, are taken in the (n-2)!/k! Melia basis, and are independent under the color-algebra Kleiss-Kuijf relations. This generalizes the color decomposition of Del Duca, Dixon, and Maltoni to an arbitrary number of quarks. The color coefficients in the new decomposition are given by compact expressions valid for arbitrary gauge group and representation. Considering the kinematic structure, we show through explicit calculations that color-kinematics duality holds for amplitudes with general configurations of gluons and massive quarks. The new (massive) amplitude relations that follow from the duality can be mapped to a well-defined subset of the familiar BCJ relations for gluons. They restrict the amplitude basis further down to (n-3)!(2k-2)/k! primitives, for two or more quark lines. We give a decomposition of the full amplitude in that basis. The presented results provide strong evidence that QCD obeys the color-kinematics duality, at least at tree level. The results are also applicable to supersymmetric and D-dimensional extensions of QCD.Johansson, HenrikOchirov, AlexanderThu, 02 Jul 2015 06:13:17 GMT01 Jul 2015arXiv:1507.00332http://cds.cern.ch/record/2030454Three-loop corrections to the soft anomalous dimension in multi-leg scattering
http://cds.cern.ch/record/2030448
We present the three-loop result for the soft anomalous dimension governing long-distance singularities of multi-leg gauge-theory scattering amplitudes of massless partons. This establishes the form of the first corrections to the dipole formula as `quadrupoles', or four-parton correlations. We compute the set of non-planar connected gluon webs involving four semi-infinite Wilson lines at three loops. The calculation is set up for non-lightlike Wilson lines, from which we extract the asymptotic lightlike limit using Mellin-Barnes techniques. The knowledge of these graphs, combined with constraints from the Regge limit, is sufficient to obtain the complete three-loop correction to the dipole formula, which can be expressed in terms of a pure combination of single-valued harmonic polylogarithms. Finally we observe that, in contrast to previous expectations, the quadrupole term in the soft anomalous dimension does not vanish in two-particle collinear limits. This implies that, starting at three loops and beyond leading colour, splitting amplitudes do depend on the colour and direction of the other partons participating in the scattering.Almelid, ØyvindDuhr, ClaudeGardi, EinanThu, 02 Jul 2015 06:13:15 GMT30 Jun 2015arXiv:1507.00047http://cds.cern.ch/record/2030448The Gravity of Dark Vortices: Effective Field Theory for Branes and Strings Carrying Localized Flux
http://cds.cern.ch/record/2029863
A Nielsen-Olesen vortex usually sits in an environment that expels the flux that is confined to the vortex, so flux is not present both inside and outside. We construct vortices for which this is not true, where the flux carried by the vortex also permeates the `bulk' far from the vortex. The idea is to mix the vortex's internal gauge flux with an external flux using off-diagonal kinetic mixing. Such `dark' vortices could play a phenomenological role in models with both cosmic strings and a dark gauge sector. When coupled to gravity they also provide explicit ultra-violet completions for codimension-two brane-localized flux, which arises in extra-dimensional models when the same flux that stabilizes extra-dimensional size is also localized on space-filling branes situated around the extra dimensions. We derive simple formulae for observables such as defect angle, tension, localized flux and on-vortex curvature when coupled to gravity, and show how all of these are insensitive to much of the microscopic details of the solutions, and are instead largely dictated by low-energy quantities. We derive the required effective description in terms of a world-sheet brane action, and derive the matching conditions for its couplings. We consider the case where the dimensions transverse to the bulk compactify, and determine how the on- and off-vortex curvatures and other bulk features depend on the vortex properties. We find that the brane-localized flux does not gravitate, but just renormalizes the tension in a magnetic-field independent way. The existence of an explicit UV completion puts the effective description of these models on a more precise footing, verifying that brane-localized flux can be consistent with sensible UV physics and resolving some apparent paradoxes that can arise with a naive (but commonly used) delta-function treatment of the brane's localization within the bulk.Burgess, C PDiener, RWilliams, MTue, 30 Jun 2015 06:08:19 GMT26 Jun 2015arXiv:1506.08095http://cds.cern.ch/record/2029863Bootstrapping correlation functions in N=4 SYM
http://cds.cern.ch/record/2028725
We describe a new approach to computing the chiral part of correlation functions of stress-tensor supermultiplets in N=4 SYM that relies on symmetries, analytic properties and the structure of the OPE only. We demonstrate that the correlation functions are given by a linear combination of chiral N=4 superconformal invariants accompanied by coefficient functions depending on the space-time coordinates only. We present the explicit construction of these invariants and show that the six-point correlation function is fixed in the Born approximation up to four constant coefficients by its symmetries. In addition, the known asymptotic structure of the correlation function in the light-like limit fixes unambiguously these coefficients up to an overall normalization. We demonstrate that the same approach can be applied to obtain a representation for the six-point NMHV amplitude that is free from any auxiliary gauge fixing parameters, does not involve spurious poles and manifests half of the dual superconformal symmetry.Chicherin, DmitryDoobary, RezaEden, BurkhardHeslop, PaulKorchemsky, Gregory PSokatchev, EmeryFri, 26 Jun 2015 18:12:10 GMT16 Jun 2015arXiv:1506.04983http://cds.cern.ch/record/2028725Introduction to Heavy Flavours
http://cds.cern.ch/record/2028701
We present a short review of heavy flavours and the main challenges given the recent experimental developments.Mahmoudi, FFri, 26 Jun 2015 17:46:04 GMT25 Jun 2015arXiv:1506.07843http://cds.cern.ch/record/2028701Detecting underabundant neutralinos
http://cds.cern.ch/record/2028672
The 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 Dark Matter, in a broad range of the parameter space. We find that for a very large range of parameters the Direct Detection experiments are/will be sensitive to underabundant neutralinos, in spite of the strong rescaling of the flux factor. The second general conclusion is that the bound $\Omega_\chi h^2 \leq 0.12$ together with the LUX (XENON1T) limits for the neutralino spin independent scattering cross sections constrain the electroweakino spectrum to be very compressed, with the mass differences between the NLSP and the LSP smaller than 40 (10) GeV, respectively, with important implications for the collider searches. The future Direct Detection experiments and the high luminosity LHC run will probe almost the entire range of the LSP and NLSP mass spectrum that is consistent with the bound $\Omega_\chi h^2 \leq 0.12$.Badziak, MarcinDelgado, AntonioOlechowski, MarekPokorski, StefanSakurai, KazukiFri, 26 Jun 2015 17:45:55 GMT23 Jun 2015arXiv:1506.07177http://cds.cern.ch/record/2028672Isotropization and hydrodynamization in weakly coupled heavy-ion collisions
http://cds.cern.ch/record/2028649
We numerically solve 2+1D effective kinetic theory of weak coupling QCD under longitudinal expansion relevant for early stages of heavy-ion collisions. We find agreement with viscous hydrodynamics and classical Yang-Mills simulations in the regimes where they are applicable. By choosing initial conditions that are motivated by color-glass-condensate framework we find that for Q=2GeV and $\alpha_s$=0.3 the system is approximately described by viscous hydrodynamics well before $\tau \lesssim 1.0$ fm/c.Kurkela, AleksiZhu, YanFri, 26 Jun 2015 17:45:51 GMT22 Jun 2015arXiv:1506.06647http://cds.cern.ch/record/2028649Integrating out lattice gauge fields
http://cds.cern.ch/record/2028555
The sign problem is a major obstacle to our understanding of the phase diagram of QCD at finite baryon density. Several numerical methods have been proposed to tackle this problem, but a full solution to the sign problem is still elusive. Motivated by this problem and by recent advances in diagrammatic Monte Carlo methods, we find a new exact representation of the partition function of pure lattice gauge theory that contains no link variables. This approach can be easily extended to include staggered fermions, and results in a diagrammatic representation of fermionic states as arrangements of monomers, dimers, and fermionic loops saturating the spacetime lattice. Our representations are exact for any value of the lattice coupling, and extend previous representations that are only valid in the strong coupling limit and at $O(\beta)$. As a concrete example, we construct a monomer-dimer-loop representation of compact lattice QED.Vairinhos, Helviode Forcrand, PhilippeFri, 26 Jun 2015 15:57:41 GMT23 Jun 2015arXiv:1506.07007http://cds.cern.ch/record/2028555Mass anomalous dimension of Adjoint QCD at large N from twisted volume reduction
http://cds.cern.ch/record/2028551
In this work we consider the $SU(N)$ gauge theory with two Dirac fermions in the adjoint representation, in the limit of large $N$. In this limit the infinite-volume physics of this model can be studied by means of the corresponding twisted reduced model defined on a single site lattice. Making use of this strategy we study the reduced model for various values of $N$ up to 289. By analyzing the eigenvalue distribution of the adjoint Dirac operator we test the conformality of the theory and extract the corresponding mass anomalous dimension.Pérez, Margarita GarcíaGonzález-Arroyo, AntonioKeegan, LiamOkawa, MasanoriFri, 26 Jun 2015 15:57:40 GMT22 Jun 2015arXiv:1506.06536http://cds.cern.ch/record/2028551Some Pathways in non-Linear Supersymmetry: Special Geometry Born-Infeld's, Cosmology and dualities
http://cds.cern.ch/record/2028406
This review is devoted to some aspects of non-linear Supersymmetry in four dimensions that can be efficiently described via nilpotent superfields, in both rigid and curved Superspace. Our focus is mainly on the partial breaking of rigid $N=2$ Supersymmetry and on a class of generalized Born-Infeld systems that originate from Special Geometry and on some prototype cosmological models, starting from the Supergravity embedding of Starobinsky inflation. However, as an aside we also review briefly some interesting two-field extensions of the Born-Infeld Lagrangian whose field equations enjoy extended duality symmetries.Ferrara, SSagnotti, AFri, 26 Jun 2015 15:38:45 GMT18 Jun 2015arXiv:1506.05730http://cds.cern.ch/record/2028406Inflationary magnetogenesis, derivative couplings and relativistic Van der Waals interactions
http://cds.cern.ch/record/2027889
When the gauge fields have derivative couplings to scalars, like in the case of the relativistic theory of Van der Waals (or Casimir-Polder) interactions, conformal invariance is broken but the magnetic and electric susceptibilities are not bound to coincide. We analyze the formation of large-scale magnetic fields in slow-roll inflation and find that they are generated at the level of few hundredths of a nG and over typical length scales between few Mpc and $100$ Mpc. Using a new time parametrization that reduces to conformal time but only for coincident susceptibilities, the gauge action is quantized while the evolution equations of the corresponding mode functions are more easily solvable. The power spectra depend on the normalized rates of variation of the two susceptibilities (or of the corresponding gauge couplings) and on the absolute value of their ratio at the beginning of inflation. We pin down explicit regions in the parameter space where all the physical requirements (i.e. the backreaction constraints, the magnetogenesis bounds and the naturalness of the initial conditions of the scenario) are jointly satisfied. Weakly coupled initial data are favoured if the gauge couplings are of the same order at the end of inflation. Duality is systematically used to simplify the analysis of the wide parameter space of the model.Giovannini, MassimoFri, 26 Jun 2015 15:01:05 GMT12 Jun 2015arXiv:1506.04186http://cds.cern.ch/record/2027889Effective field theory approach to $b\to s\ell\ell^{(\prime)}$, $B\to K^{(*)}\nu\bar{\nu}$ and $B\to D^{(*)}\tau\nu$ with third generation couplings
http://cds.cern.ch/record/2024070
LHCb reported anomalies in $B\to K^* \mu^+\mu^-$, $B_s\to\phi\mu^+\mu^-$ and $R(K)=B\to K \mu^+\mu^-/B\to K e^+e^-$. Furthermore, BaBar, BELLE and LHCb found hints for the violation of lepton flavour universality violation in $R(D^{(*)})=B\to D^{(*)}\tau\nu/B\to D^{(*)}\ell\nu$. In this note we reexamine these decays and their correlations to $B\to K^{(*)}\nu\bar{\nu}$ using gauge invariant dim-6 operators. For the numerical analysis we focus on scenarios in which new physics couples, in the interaction eigenbasis, to third generation quarks and lepton only. We conclude that such a setup can explain the $b\to s\mu^+\mu^-$ data simultaneously with $R(D^{(*)})$ for small mixing angles in the lepton sector (of the order of $\pi/16$) and very small mixing angles in the quark sector (smaller than $V_{cb}$). In these region of parameter space $B\to K^{(*)}\tau\mu$ and $B_s\to \tau\mu$ can be order $10^{-6}$. Possible UV completions are briefly discussed.Calibbi, LorenzoCrivellin, AndreasOta, ToshihikoThu, 11 Jun 2015 06:33:10 GMT08 Jun 2015arXiv:1506.02661http://cds.cern.ch/record/2024070Monojet Searches for MSSM Simplified Models
http://cds.cern.ch/record/2022996
We explore the implications of monojet searches at hadron colliders in the MSSM. To quantify the impact of monojet searches, we consider simplified MSSM scenarios with neutralino dark matter. The monojet results of the LHC Run 1 are reinterpreted in the context of several MSSM simplified scenarios, and the complementarity with direct SUSY search results is highlighted. We also investigate the reach of monojet searches for the Run 2, as well as for future higher energy hadron colliders.Arbey, ABattaglia, MMahmoudi, FTue, 09 Jun 2015 05:38:05 GMT06 Jun 2015arXiv:1506.02148http://cds.cern.ch/record/2022996The Yang-Mills gradient flow and renormalization
http://cds.cern.ch/record/2021265
In this proceedings contribution we will review the main ideas behind the many recent works that apply the gradient flow to the determination of the renormalized coupling and the renormalization of composite operators. We will pay special attention to the continuum extrapolation of flow quantities.Ramos, AlbertoWed, 03 Jun 2015 05:58:48 GMT30 May 2015arXiv:1506.00118http://cds.cern.ch/record/2021265Backreaction effects on the matter side of Einstein's field equations
http://cds.cern.ch/record/2021234
Recently, we have derived a novel and compact expression for how perturbations in the matter fields of the cosmological fluid can lead to deviations from the standard Friedmann equations. Remarkably, the dissipative damping of velocity perturbations by bulk and shear viscosity in the dark sector can modify the expansion history of the universe on arbitrarily large scales. In universes in which this effect is sufficiently sizeable, it could account for the acceleration of the cosmological expansion. But even if dark matter should be less viscous and if the effect would be correspondingly smaller, it may have observable consequences in the era of precision cosmology. Here, we review the origin of this backreaction effect and possibilities to constrain it further.Floerchinger, StefanTetradis, NikolaosWiedemann, Urs AchimWed, 03 Jun 2015 05:54:26 GMT01 Jun 2015arXiv:1506.00407http://cds.cern.ch/record/2021234Aspects of Quadratic Gravity
http://cds.cern.ch/record/2020526
We discuss quadratic gravity where terms quadratic in the curvature tensor are included in the action. After reviewing the corresponding field equations, we analyze in detail the physical propagating modes in some specific backgrounds. First we confirm that the pure $R^2$ theory is indeed ghost free. Then we point out that for flat backgrounds the pure $R^2$ theory propagates only a scalar massless mode and no spin-two tensor mode. However, the latter emerges either by expanding the theory around curved backgrounds like de Sitter or anti-de Sitter, or by changing the long-distance dynamics by introducing the standard Einstein term. In both cases, the theory is modified in the infrared and a propagating graviton is recovered. Hence we recognize a subtle interplay between the UV and IR properties of higher order gravity. We also calculate the corresponding Newton's law for general quadratic curvature theories. Finally, we discuss how quadratic actions may be obtained from a fundamental theory like string- or M-theory. We demonstrate that string theory on non-compact $CY_3$ manifolds, like a line bundle over $\mathbb{CP}^2$, may indeed lead to gravity dynamics determined by a higher curvature action.Alvarez-Gaume, LuisKehagias, AlexKounnas, CostasLust, DieterRiotto, AntonioSat, 30 May 2015 07:36:56 GMT28 May 2015arXiv:1505.07657http://cds.cern.ch/record/2020526GMSB with Light Stops
http://cds.cern.ch/record/2020510
Gauge mediated supersymmetry breaking (GMSB) is an elegant mechanism to transmit supersymmetry breaking from the hidden to the MSSM observable sector, which solves the supersymmetric flavor problem. However the smallness of the generated stop mixing requires superheavy stops to reproduce the experimental value of the Higgs mass. Two possible ways out are: i) To extend GMSB by direct superpotential messenger-MSSM Yukawa couplings to generate sizeable mixing, thus reintroducing the flavor problem; ii) To extend the MSSM Higgs sector with singlets and/or triplets providing extra tree-level corrections to the Higgs mass. Singlets will not get any soft mass from GMSB and triplets will contribute to the $\rho$ parameter which could be an issue. In this paper we explore the second way by introducing extra supersymmetric triplets with hypercharges $Y=(0,\pm 1)$, with a tree-level custodial $SU(2)_L\otimes SU(2)_R$ global symmetry in the Higgs sector protecting the $\rho$ parameter: a supersymmetric generalization of the Georgi-Machacek model, dubbed as supersymmetric custodial triplet model (SCTM). The renormalization group running from the messenger to the electroweak scale mildly breaks the custodial symmetry. We will present realistic low-scale scenarios (with the NLSP being a Bino-like neutralino or the right-handed stau) based on general (non-minimal) gauge mediation and consistent with all present experimental data. Their main features are: i) Light ($\sim 1$ TeV) stops; ii) Exotic couplings ($H^\pm W^\mp Z$ and $H^{\pm\pm} W^\mp W^\mp$) absent in the MSSM and proportional to the triplets VEV, $v_\Delta$; and, iii) A possible (measurable) universality breaking of the Higgs couplings $\lambda_{WZ}=r_{WW}/r_{ZZ}\neq 1$.Delgado, AntonioGarcia-Pepin, MateoQuiros, MarianoSat, 30 May 2015 07:32:59 GMT27 May 2015arXiv:1505.07469http://cds.cern.ch/record/2020510Higgs portal valleys, stability and inflation
http://cds.cern.ch/record/2020444
If the top quark is heavy enough, the Standard Model potential is unstable at large Higgs values. This is particularly problematic during inflation, which sources large perturbations of the Higgs. The instability could be cured by a threshold effect induced by a scalar with a large vacuum expectation value and directly connected to the Standard Model through a Higgs portal coupling. However, we find that in a minimal model in which the scalar generates inflation, this mechanism does not stabilize the potential because the mass required for inflation is beyond the instability scale. On the other hand, if the potential is absolutely stable, successful inflation in agreement with current CMB data can occur along a valley of the potential with a Mexican hat profile. We revisit the stability conditions, independently of inflation, and clarify that the threshold effect cannot work if the Higgs portal coupling is too small. We also show that inflation in a false Higgs vacuum appearing radiatively for a tuned ratio of the Higgs and top masses leads to an amplitude of primordial gravitational waves that is far too high, ruling out this possibility.Ballesteros, GuillermoTamarit, CarlosSat, 30 May 2015 07:20:12 GMT27 May 2015arXiv:1505.07476http://cds.cern.ch/record/2020444The Fraternal WIMP Miracle
http://cds.cern.ch/record/2019461
We identify and analyze thermal dark matter candidates in the fraternal twin Higgs model and its generalizations. The relic abundance of fraternal twin dark matter is set by twin weak interactions, with a scale tightly tied to the weak scale of the Standard Model by naturalness considerations. As such, the dark matter candidates benefit from a "fraternal WIMP miracle," reproducing the observed dark matter abundance for dark matter masses between 10 and 100 GeV. However, the couplings dominantly responsible for dark matter annihilation do not lead to interactions with the visible sector. The direct detection rate is instead set via fermionic Higgs portal interactions, which are likewise constrained by naturalness considerations but parametrically weaker than those leading to dark matter annihilation. The predicted direct detection cross section is close to current LUX bounds and presents an opportunity for the next generation of direct detection experiments.Craig, NathanielKatz, AndreyThu, 28 May 2015 06:08:59 GMT26 May 2015arXiv:1505.07113http://cds.cern.ch/record/2019461Calculations of Inflaton Decays and Reheating: with Applications to No-Scale Inflation Models
http://cds.cern.ch/record/2019444
We discuss inflaton decays and reheating in no-scale Starobinsky-like models of inflation, calculating the effective equation-of-state parameter, $w$, during the epoch of inflaton decay, the reheating temperature, $T_{\rm reh}$, and the number of inflationary e-folds, $N_*$, comparing analytical approximations with numerical calculations. We then illustrate these results with applications to models based on no-scale supergravity and motivated by generic string compactifications, including scenarios where the inflaton is identified as an untwisted-sector matter field with direct Yukawa couplings to MSSM fields, and where the inflaton decays via gravitational-strength interactions. Finally, we use our results to discuss the constraints on these models imposed by present measurements of the scalar spectral index $n_s$ and the tensor-to-scalar perturbation ratio $r$, converting them into constraints on $N_*$, the inflaton decay rate and other parameters of specific no-scale inflationary models.Ellis, JohnGarcia, Marcos A GNanopoulos, Dimitri VOlive, Keith AThu, 28 May 2015 06:08:53 GMT26 May 2015arXiv:1505.06986http://cds.cern.ch/record/2019444Instanton Operators and the Higgs Branch at Infinite Coupling
http://cds.cern.ch/record/2018333
The richness of 5d $\mathcal{N}=1$ theories with a UV fixed point at infinite coupling is due to the existence of local disorder operators known as instanton operators. By considering the Higgs branch of $SU(2)$ gauge theories with $N_f \leq 7$ flavours at finite and infinite coupling, we write down the explicit chiral ring relations between instanton operators, the glueball superfield and mesons. Exciting phenomena appear at infinite coupling: the glueball superfield is no longer nilpotent and the classical chiral ring relations are quantum corrected by instanton operators bilinears. We also find expressions for the dressing of instanton operators of arbitrary charge. The same analysis is performed for $USp(2k)$ with an antisymmetric hypermultiplet and pure $SU(N)$ gauge theories.Cremonesi, StefanoFerlito, GiuliaHanany, AmihayMekareeya, NoppadolTue, 26 May 2015 05:52:39 GMT23 May 2015arXiv:1505.06302http://cds.cern.ch/record/2018333Precise determination of the Higgs mass in supersymmetric models with vectorlike tops and the impact on naturalness in minimal GMSB
http://cds.cern.ch/record/2018135
We present a precise analysis of the Higgs mass corrections stemming from vectorlike top partners in supersymmetric models. We reduce the theoretical uncertainty compared to previous studies in the following aspects: (i) including the one-loop threshold corrections to SM gauge and Yukawa couplings due to the presence of the new states to obtain the $\bar{\text{DR}}$ parameters entering all loop calculations, (ii) including the full momentum dependence at one-loop, and (iii) including all two-loop corrections but the ones involving $g_1$ and $g_2$. We find that the additional threshold corrections are very important and can give the largest effect on the Higgs mass. However, we identify also parameter regions where the new two-loop effects can be more important than the ones of the MSSM and change the Higgs mass prediction by up to 10 GeV. This is for instance the case in the low $\tan\beta$, small $M_A$ regime. We use these results to calculate the electroweak fine-tuning of an UV complete variant of this model. For this purpose, we add a complete $\textbf{10}$ and $\bar{\textbf{10}}$ representation of $SU(5)$ to the MSSM particle content. We embed this model in minimal Gauge Mediated Supersymmetry Breaking and calculate the electroweak fine-tuning with respect to all important parameters. It turns out that the limit on the gluino mass becomes more important for the fine-tuning than the Higgs mass measurements which is easily to satisfy in this setup.Nickel, KilianStaub, FlorianMon, 25 May 2015 05:25:39 GMT22 May 2015arXiv:1505.06077http://cds.cern.ch/record/2018135Consistent truncations of M-theory for general SU(2) structures
http://cds.cern.ch/record/2017974
In seven dimensions any spin manifold admits an SU(2) structure and therefore very general M-theory compactifications have the potential to allow for a reduction to N=4 gauged supergravity. We perform this general SU(2) reduction and give the relation of SU(2) torsion classes and fluxes to gaugings in the N=4 theory. We furthermore show explicitly that this reduction is a consistent truncation of the eleven-dimensional theory, in other words classical solutions of the reduced theory also solve the eleven-dimensional equations of motion. This reduction generalizes previous M-theory reductions on Tri-Sasakian manifolds and type IIA reductions on Calabi-Yau manifolds of vanishing Euler number. Moreover, it can also be applied to compactifications on certain G2 holonomy manifolds and to more general flux backgrounds.Triendl, HagenSat, 23 May 2015 05:53:15 GMT20 May 2015arXiv:1505.05526http://cds.cern.ch/record/2017974