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QCD next-to-leading order predictions matched to parton showers for vector-like quark models
http://cds.cern.ch/record/2225709
Vector-like quarks are featured by a wealth of beyond the Standard Model theories and are consequently an important goal of many LHC searches for new physics. Those searches, as well as most related phenomenological studies, however rely on predictions evaluated at the leading-order accuracy in QCD and consider well-defined simplified benchmark scenarios. Adopting an effective bottom-up approach, we compute next-to-leading-order predictions for vector-like-quark pair-production and single production in association with jets, with a weak or with a Higgs boson in a general new physics setup. We additionally compute vector-like-quark contributions to the production of a pair of Standard Model bosons at the same level of accuracy. For all processes under consideration, we focus both on total cross sections and on differential distributions, most these calculations being performed for the first time in our field. As a result, our work paves the way to precise extraction of experimental limits on vector-like quarks thanks to an accurate control of the shapes of the relevant observables and emphasize the extra handles that could be provided by novel vector-like-quark probes never envisaged so farFuks, BenjaminShao, Hua-ShengTue, 18 Oct 2016 06:01:20 GMT14 Oct 2016arXiv:1610.04622http://cds.cern.ch/record/2225709['arXiv:1610.04622']arXiv:1610.04622Compensating strong coupling with large charge
http://cds.cern.ch/record/2225343
We study (conformal) field theories with global symmetries in the sector where the value of the global charge $Q$ is large. We find (as expected) that the low energy excitations of this sector are described by the general form of Goldstone's theorem in the non-relativistic regime. We also derive the unexpected result, first presented in [Hellerman:2015], that the effective field theory describing such sector of fixed $Q$ contains effective couplings $\lambda_{\text{eff}}\sim \lambda^b /Q^{a}$, where $\lambda$ is the original coupling. Hence, large charge leads to weak coupling. In the last section of the paper we present an outline of how to compute anomalous dimensions in this limit.Alvarez-Gaume, LuisLoukas, OrestisOrlando, DomenicoReffert, SusanneMon, 17 Oct 2016 05:23:03 GMT14 Oct 2016arXiv:1610.04495http://cds.cern.ch/record/2225343['arXiv:1610.04495']arXiv:1610.04495Seven-Disk Manifold, alpha-attractors and B-modes
http://cds.cern.ch/record/2224414
Cosmological alpha-attractor models in \cN=1 supergravity are based on hyperbolic geometry of a Poincar\'e disk with the radius square {\cal R}^2=3\alpha. The predictions for the B-modes, r\approx 3\alpha {4\over N^2}, depend on moduli space geometry and are robust for a rather general class of potentials. Here we notice that starting with M-theory compactified on a 7-manifold with G_2 holonomy, with a special choice of Betti numbers, one can obtain d=4 \cN=1 supergravity with rank 7 scalar coset \Big[{SL(2)\over SO(2)}\Big]^7. In a model where these 7 unit size Poincar\'e disks have identified moduli one finds that 3 alpha =7. Assuming that the moduli space geometry of the phenomenological models is inherited from this version of M-theory, one would predict r \approx 10^{-2} for 53 e-foldings. We also describe the related maximal supergravity and M/string theory models leading to preferred values 3 alpha =1,2,3,4,5,6,7.Ferrara, SergioKallosh, RenataFri, 14 Oct 2016 05:50:02 GMT13 Oct 2016arXiv:1610.04163http://cds.cern.ch/record/2224414['arXiv:1610.04163']arXiv:1610.04163Six-dimensional Origin of $\mathcal{N}=4$ SYM with Duality Defects
http://cds.cern.ch/record/2224132
We study the topologically twisted compactification of the 6d $(2,0)$ M5-brane theory on an elliptically fibered K\"ahler three-fold preserving two supercharges. We show that upon reducing on the elliptic fiber, the 4d theory is $\mathcal{N}=4$ Super-Yang Mills, with varying complexified coupling $\tau$, in the presence of defects. For abelian gauge group this agrees with the so-called duality twisted theory, and we determine a non-abelian generalization to $U(N)$. When the elliptic fibration is singular, the 4d theory contains 3d walls (along the branch-cuts of $\tau$) and 2d surface defects, around which the 4d theory undergoes $SL(2,\mathbb{Z})$ duality transformations. Such duality defects carry chiral fields, which from the 6d point of view arise as modes of the two-form $B$ in the tensor multiplet. Each duality defect has a flavor symmetry associated to it, which is encoded in the structure of the singular elliptic fiber above the defect. Generically 2d surface defects will intersect in points in 4d, where there is an enhanced flavor symmetry. The 6d point of view provides a complete characterization of this 4d-3d-2d-0d `Matroshka'-defect configuration.Assel, BenjaminSchafer-Nameki, SakuraThu, 13 Oct 2016 06:17:42 GMT12 Oct 2016arXiv:1610.03663http://cds.cern.ch/record/2224132['arXiv:1610.03663']arXiv:1610.03663Worm Algorithm for CP(N-1) Model
http://cds.cern.ch/record/2223059
The CP(N-1) model in 2D is an interesting toy model for 4D QCD as it possesses confinement, asymptotic freedom and a non-trivial vacuum structure. Due to the lower dimensionality and the absence of fermions, the computational cost for simulating 2D CP(N-1) on the lattice is much lower than that for simulating 4D QCD. However, to our knowledge, no efficient algorithm for simulating the lattice CP(N-1) model has been tested so far, which also works at finite density. To this end we propose a new type of worm algorithm which is appropriate to simulate the lattice CP(N-1) model in a dual, flux-variables based representation, in which the introduction of a chemical potential does not give rise to any complications. In addition to the usual worm moves where a defect is just moved from one lattice site to the next, our algorithm additionally allows for worm-type moves in the internal variable space of single links, which accelerates the Monte Carlo evolution. We use our algorithm to compare the two popular CP(N-1) lattice actions and exhibit marked differences in their approach to the continuum limit.Rindlisbacher, Tobiasde Forcrand, PhilippeSat, 08 Oct 2016 05:49:24 GMT05 Oct 2016arXiv:1610.01435http://cds.cern.ch/record/2223059['arXiv:1610.01435']arXiv:1610.01435Time evolution of linearized gauge field fluctuations on a real-time lattice
http://cds.cern.ch/record/2223057
Classical real-time lattice simulations play an important role in understanding non-equilibrium phenomena in gauge theories and are used in particular to model the prethermal evolution of heavy-ion collisions. Due to instabilities, small quantum fluctuations on top of the classical background may significantly affect the dynamics of the system. In this paper we argue for the need for a numerical calculation of a system of classical gauge fields and small linearized fluctuations in a way that keeps the separation between the two manifest. We derive and test an explicit algorithm to solve these equations on the lattice, maintaining gauge invariance and Gauss's law.Kurkela, AleksiLappi, TuomasPeuron, JarkkoSat, 08 Oct 2016 05:49:21 GMT05 Oct 2016arXiv:1610.01355http://cds.cern.ch/record/2223057['arXiv:1610.01355']arXiv:1610.01355Mass Formulae for Broken Supersymmetry in Curved Space-Time
http://cds.cern.ch/record/2219927
We derive the mass formulae for ${\cal N}=1$, $D=4$ matter-coupled Supergravity for broken (and unbroken) Supersymmetry in curved space-time. These formulae are applicable to de Sitter configurations as is the case for inflation. For unbroken Supersymmetry in anti-de Sitter (AdS) one gets the mass relations modified by the AdS curvature. We compute the mass relations both for the potential and its derivative non-vanishing.Ferrara, SergioVan Proeyen, AntoineWed, 28 Sep 2016 06:01:04 GMT27 Sep 2016arXiv:1609.08480http://cds.cern.ch/record/2219927['arXiv:1609.08480']arXiv:1609.08480Gauged Lepton Flavour
http://cds.cern.ch/record/2217407
The gauging of the lepton flavour group is considered in the Standard Model context and in its extension with three right-handed neutrinos. The anomaly cancellation conditions lead to a Seesaw mechanism as underlying dynamics for all leptons; requiring in addition a phenomenologically viable setup leads to Majorana masses for the neutral sector: the type I Seesaw Lagrangian in the Standard Model case and the inverse Seesaw in the extended model. Within the minimal extension of the scalar sector, the Yukawa couplings are promoted to scalar fields in the bifundamental of the flavour group. The resulting low-energy Yukawa couplings are proportional to inverse powers of the vacuum expectation values of those scalars; the protection against flavour changing neutral currents differs from that of Minimal Flavor Violation. In all cases, the $\mu-\tau$ flavour sector exhibits rich and promising phenomenological signals.Alonso, RMartinez, E FernandezGavela, M BGrinstein, BMerlo, LQuilez, PThu, 22 Sep 2016 06:22:55 GMT19 Sep 2016arXiv:1609.05902http://cds.cern.ch/record/2217407['arXiv:1609.05902']arXiv:1609.05902Angular Structure of Jet Quenching Within a Hybrid Strong/Weak Coupling Model
http://cds.cern.ch/record/2216782
Within the context of a hybrid strong/weak coupling model of jet quenching, we study the modification of the angular distribution of the energy within jets in heavy ion collisions, as partons within jet showers lose energy and get kicked as they traverse the strongly coupled plasma produced in the collision. To describe the dynamics transverse to the jet axis, we add the effects of transverse momentum broadening into our hybrid construction, introducing a parameter $K\equiv \hat q/T^3$ that governs its magnitude. We show that, because of the quenching of the energy of partons within a jet, even when $K\neq 0$ the jets that survive with some specified energy in the final state are narrower than jets with that energy in proton-proton collisions. For this reason, many standard observables are rather insensitive to $K$. We propose a new differential jet shape ratio observable in which the effects of transverse momentum broadening are apparent. We also analyze the response of the medium to the passage of the jet through it, noting that the momentum lost by the jet appears as the momentum of a wake in the medium. After freezeout this wake becomes soft particles with a broad angular distribution but with net momentum in the jet direction. We show that the particles coming from the response of the medium to the momentum and energy deposited in it leads to a correlation between the momentum of soft particles well separated from the jet in angle with the direction of the jet momentum, and find qualitative but not quantitative agreement with experimental data on observables designed to extract such a correlation. By confronting the results that we obtain upon introducing transverse momentum broadening and the response of the medium to the jet with available jet data, we highlight the importance of these processes for understanding the internal, soft, angular structure of high energy jets.Casalderrey-Solana, JorgeGulhan, DogaMilhano, GuilhermePablos, DanielRajagopal, KrishnaTue, 20 Sep 2016 05:53:15 GMT19 Sep 2016arXiv:1609.05842http://cds.cern.ch/record/2216782['arXiv:1609.05842']arXiv:1609.05842Higgs-Stoponium Mixing Near the Stop-Antistop Threshold
http://cds.cern.ch/record/2216753
Supersymmetric extensions of the standard model contain additional heavy neutral Higgs bosons that are coupled to heavy scalar top quarks (stops). This system exhibits interesting field theoretic phenomena when the Higgs mass is close to the stop-antistop production threshold. Existing work in the literature has examined the digluon-to-diphoton cross section near threshold and has focused on enhancements in the cross section that might arise either from the perturbative contributions to the Higgs-to-digluon and Higgs-to-diphoton form factors or from mixing of the Higgs boson with stoponium states. Near threshold, enhancements in the relevant amplitudes that go as inverse powers of the stop-antistop relative velocity require resummations of perturbation theory and/or nonperturbative treatments. We present a complete formulation of threshold effects at leading order in the stop-antistop relative velocity in terms of nonrelativistic effective field theory. We give detailed numerical calculations for the case in which the stop-antistop Green's function is modeled with a Coulomb-Schr\"odinger Green's function. We find several general effects that do not appear in a purely perturbative treatment. Higgs-stop-antistop mixing effects displace physical masses from the threshold region, thereby rendering the perturbative threshold enhancements inoperative. In the case of large Higgs-stop-antistop couplings, the displacement of a physical state above threshold substantially increases its width, owing to its decay width to a stop-antistop pair, and greatly reduces its contribution to the cross section.Bodwin, Geoffrey TChung, Hee SokWagner, Carlos E MTue, 20 Sep 2016 05:53:09 GMT15 Sep 2016arXiv:1609.04831http://cds.cern.ch/record/2216753['arXiv:1609.04831']arXiv:1609.04831Starobinsky-Like Inflation and Neutrino Masses in a No-Scale SO(10) Model
http://cds.cern.ch/record/2216709
Using a no-scale supergravity framework, we construct an SO(10) model that makes predictions for cosmic microwave background observables similar to those of the Starobinsky model of inflation, and incorporates a double-seesaw model for neutrino masses consistent with oscillation experiments and late-time cosmology. We pay particular attention to the behaviour of the scalar fields during inflation and the subsequent reheating.Ellis, JohnGarcia, Marcos A GNagata, NatsumiNanopoulos, Dimitri VOlive, Keith ATue, 20 Sep 2016 05:48:53 GMT19 Sep 2016arXiv:1609.05849http://cds.cern.ch/record/2216709['arXiv:1609.05849']arXiv:1609.05849Parametric Resonance in the Early Universe - A Fitting Analysis
http://cds.cern.ch/record/2216638
Particle production via parametric resonance in the early Universe, is a non-perturbative, non-linear and out-of-equilibrium phenomenon. Although it is a well studied topic, whenever a new scenario exhibits parametric resonance, a full re-analysis is normally required. To avoid this tedious task, many works present often only a simplified linear treatment of the problem. In order to surpass this circumstance in the future, we provide a fitting analysis of parametric resonance through all its relevant stages: initial linear growth, non-linear evolution, and relaxation towards equilibrium. Using lattice simulations in an expanding grid in $3+1$ dimensions, we parametrise the dynamics' outcome scanning over the relevant ingredients: role of the oscillatory field, particle coupling strength, initial conditions, and background expansion rate. We emphasise the inaccuracy of the linear calculation of the decay time of the oscillatory field, and propose a more appropriate definition of this scale based on the subsequent non-linear dynamics. We provide simple fits to the relevant time scales and particle energy fractions at each stage. Our fits can be applied to post-inflationary preheating scenarios, where the oscillatory field is the inflaton, or to spectator-field scenarios, where the oscillatory field can be e.g.~a curvaton, or the Standard Model Higgs.Figueroa, Daniel GTorrenti, FranciscoTue, 20 Sep 2016 05:48:43 GMT16 Sep 2016arXiv:1609.05197http://cds.cern.ch/record/2216638['arXiv:1609.05197']arXiv:1609.05197Weakening Gravity on Redshift-Survey Scales with Kinetic Matter Mixing
http://cds.cern.ch/record/2213703
We explore general scalar-tensor models in the presence of a kinetic mixing between matter and the scalar field, which we call Kinetic Matter Mixing. In the frame where gravity is de-mixed from the scalar this is due to disformal couplings of matter species to the gravitational sector, with disformal coefficients that depend on the gradient of the scalar field. In the frame where matter is minimally coupled, it originates from the so-called beyond Horndeski quadratic Lagrangian. We extend the Effective Theory of Interacting Dark Energy by allowing disformal coupling coefficients to depend on the gradient of the scalar field as well. In this very general approach, we derive the conditions to avoid ghost and gradient instabilities and we define Kinetic Matter Mixing independently of the frame metric used to described the action. We study its phenomenological consequences for a $\Lambda$CDM background evolution, first analytically on small scales. Then, we compute the matter power spectrum and the angular spectra of the CMB anisotropies and the CMB lensing potential, on all scales. We employ the public version of COOP, a numerical Einstein-Boltzmann solver that implements very general scalar-tensor modifications of gravity. Rather uniquely, Kinetic Matter Mixing weakens gravity on short scales, predicting a lower $\sigma_8$ with respect to the $\Lambda$CDM case. We propose this as a possible solution to the tension between the CMB best-fit model and low-redshift observables.D'Amico, GuidoHuang, ZhiqiMancarella, MicheleVernizzi, FilippoWed, 07 Sep 2016 06:35:58 GMT05 Sep 2016arXiv:1609.01272http://cds.cern.ch/record/2213703['arXiv:1609.01272']arXiv:1609.01272A Higgs in the Warped Bulk and LHC signals
http://cds.cern.ch/record/2210901
Warped models with the Higgs in the bulk can generate light Kaluza-Klein (KK) Higgs modes consistent with the electroweak precision analysis. The first KK mode of the Higgs (h_{1}) could lie in the 1-2 TeV range in the models with a bulk custodial symmetry. We find that the h_{1} is gaugephobic and decays dominantly into a t\bar{t} pair. We also discuss the search strategy for h_{1} decaying to t\bar{t} at the Large Hadron Collider. We used substructure tools to suppress the large QCD background associated with this channel. We find that h_{1} can be probed at the LHC run-2 with an integrated luminosity of 300 fb^{-1}.Mahmoudi, FMaitra, UManglani, NSridhar, KMon, 29 Aug 2016 05:48:20 GMT26 Aug 2016arXiv:1608.07407http://cds.cern.ch/record/2210901['arXiv:1608.07407']arXiv:1608.07407Gauge-Independent Scales Related to the Standard Model Vacuum Instability
http://cds.cern.ch/record/2210252
The measured (central) values of the Higgs and top quark masses indicate that the Standard Model (SM) effective potential develops an instability at high field values. The scale of this instability, determined as the Higgs field value at which the potential drops below the electroweak minimum, is about $10^{11}$ GeV. However, such a scale is unphysical as it is not gauge-invariant and suffers from a gauge-fixing uncertainty of up to two orders of magnitude. Subjecting our system, the SM, to several probes of the instability (adding higher order operators to the potential; letting the vacuum decay through critical bubbles; heating up the system to very high temperature; inflating it) and asking in each case physical questions, we are able to provide several gauge-invariant scales related with the Higgs potential instability.Espinosa, Jose RGarny, MathiasKonstandin, ThomasRiotto, AntonioThu, 25 Aug 2016 06:18:58 GMT24 Aug 2016arXiv:1608.06765http://cds.cern.ch/record/2210252['arXiv:1608.06765']arXiv:1608.06765Glauber theory and the quantum coherence of curvature inhomogeneities
http://cds.cern.ch/record/2209738
The curvature inhomogeneities are systematically scrutinized in the framework of the Glauber approach. The amplified quantum fluctuations of the scalar and tensor modes of the geometry are shown to be first-order coherent while the interference of the corresponding intensities is larger than in the case of Bose-Einstein correlations. After showing that the degree of second-order coherence does not suffice to characterize unambiguously the curvature inhomogeneities, we argue that direct analyses of the degrees of third and fourth-order coherence are necessary to discriminate between different correlated states and to infer more reliably the statistical properties of the large-scale fluctuations. We speculate that the moments of the multiplicity distributions of the relic phonons might be observationally accessible thanks to new generations of instruments able to count the single photons of the Cosmic Microwave Background in the THz region.Giovannini, MassimoWed, 24 Aug 2016 06:09:22 GMT20 Aug 2016arXiv:1608.05843http://cds.cern.ch/record/2209738['arXiv:1608.05843']arXiv:1608.05843The Super-GUT CMSSM Revisited
http://cds.cern.ch/record/2208907
We revisit minimal supersymmetric SU(5) grand unification (GUT) models in which the soft supersymmetry-breaking parameters of the minimal supersymmetric Standard Model (MSSM) are universal at some input scale, $M_{in}$, above the supersymmetric gauge coupling unification scale, $M_{GUT}$. As in the constrained MSSM (CMSSM), we assume that the scalar masses and gaugino masses have common values, $m_0$ and $m_{1/2}$ respectively, at $M_{in}$, as do the trilinear soft supersymmetry-breaking parameters $A_0$. Going beyond previous studies of such a super-GUT CMSSM scenario, we explore the constraints imposed by the lower limit on the proton lifetime and the LHC measurement of the Higgs mass, $m_h$. We find regions of $m_0$, $m_{1/2}$, $A_0$ and the parameters of the SU(5) superpotential that are compatible with these and other phenomenological constraints such as the density of cold dark matter, which we assume to be provided by the lightest neutralino. Typically, these allowed regions appear for $m_0$ and $m_{1/2}$ in the multi-TeV region, for suitable values of the unknown SU(5) GUT-scale phases and superpotential couplings, and with the ratio of supersymmetric Higgs vacuum expectation values $\tan \beta \lesssim 6$.Ellis, JohnEvans, Jason LMustafayev, AzarNagata, NatsumiOlive, Keith AFri, 19 Aug 2016 06:23:44 GMT18 Aug 2016arXiv:1608.05370http://cds.cern.ch/record/2208907['arXiv:1608.05370']arXiv:1608.05370Two-loop scale-invariant scalar potential and quantum effective operators
http://cds.cern.ch/record/2208904
Spontaneous breaking of quantum scale invariance may provide a solution to the hierarchy and cosmological constant problems. In a scale-invariant regularization, we compute the two-loop potential of a higgs-like scalar $\phi$ in theories in which scale symmetry is broken only spontaneously by the dilaton ($\sigma$). Its vev $\langle\sigma\rangle$ generates the DR subtraction scale ($\mu\sim\langle\sigma\rangle$), which avoids the explicit scale symmetry breaking by traditional regularizations (where $\mu$=fixed scale). The two-loop potential contains effective operators of non-polynomial nature as well as new corrections, beyond those obtained with explicit breaking ($\mu$=fixed scale). These operators have the form: $\phi^6/\sigma^2$, $\phi^8/\sigma^4$, etc, which generate an infinite series of higher dimensional polynomial operators upon expansion about $\langle\sigma\rangle\gg \langle\phi\rangle$, where such hierarchy is arranged by {\it one} initial, classical tuning. These operators emerge at the quantum level from evanescent interactions ($\propto\epsilon$) between $\sigma$ and $\phi$ that vanish in $d=4$ but are demanded by classical scale invariance in $d=4-2\epsilon$. The Callan-Symanzik equation of the two-loop potential is respected and the two-loop beta functions of the couplings differ from those of the same theory regularized with $\mu=$fixed scale. Therefore the running of the couplings enables one to distinguish between spontaneous and explicit scale symmetry breaking.Ghilencea, D MLalak, ZOlszewski, PFri, 19 Aug 2016 06:23:44 GMT18 Aug 2016arXiv:1608.05336http://cds.cern.ch/record/2208904['arXiv:1608.05336']arXiv:1608.05336Chiral Heterotic Strings with Positive Cosmological Constant
http://cds.cern.ch/record/2208448
We present explicit examples of semi-realistic heterotic models with spontaneously broken supersymmetry, which dynamically lead to breaking scales much smaller than $M_{\rm Planck}$ and exponentially small positive values for the cosmological constant. Contrary to field theoretic intuition, we find that the global structure of the effective potential is significantly affected by contributions of massive and non-level matched string states and we investigate the conditions that dynamically ensure a number of desired properties.Florakis, IoannisRizos, JohnWed, 17 Aug 2016 07:57:48 GMT16 Aug 2016arXiv:1608.04582http://cds.cern.ch/record/2208448['arXiv:1608.04582']arXiv:1608.04582Simulating V+jet processes in heavy ion collisions with JEWEL
http://cds.cern.ch/record/2207127
Processes in which a jet recoils against an electroweak boson complement studies of jet quenching in heavy ion collisions at the LHC. As the boson does not interact strongly it escapes the dense medium unmodified and thus provides a more direct access to the hard scattering kinematics than can be obtained in di-jet events. First measurements of jet modification in these processes are now available from the LHC experiments and will improve greatly with better statistics in the future. We present an extension of JEWEL to boson-jet processes. JEWEL is a dynamical framework for jet evolution in a dense background based on perturbative QCD, that is in agreement with a large variety of jet observables. We also obtain a good description of the CMS and ATLAS data for y+jet and Z+jet processes at 2.76 TeV and 5.02 TeV.Elayavalli, Raghav KunnawalkamZapp, Korinna ChristineThu, 11 Aug 2016 09:48:25 GMT10 Aug 2016arXiv:1608.03099http://cds.cern.ch/record/2207127['arXiv:1608.03099']arXiv:1608.03099Associated production of a quarkonium and a Z boson at one loop in a quark-hadron-duality approach
http://cds.cern.ch/record/2207118
In view of the large discrepancy about the associated production of a prompt $J/\psi$ and a $Z$ boson between the ATLAS data at $\sqrt{s}=8$ TeV and theoretical predictions for Single Parton Scattering (SPS) contributions, we perform an evaluation of the corresponding cross section at one loop accuracy (Next-to-Leading Order, NLO) in a quark-hadron-duality approach, also known as the Colour-Evaporation Model (CEM). This work is motivated by (i) the extremely disparate predictions based on the existing NRQCD fits conjugated with the absence of a full NLO NRQCD computation and (ii) the fact that we believe that such an evaluation provides a likely upper limit of the SPS cross section. In addition to these theory improvements, we argue that the ATLAS estimation of the Double Parton Scattering (DPS) yield may be underestimated by a factor as large as 3 which then reduces the size of the SPS yield extracted from the ATLAS data. Our NLO SPS evaluation also allows us to set an upper limit on $\sigma_{\rm eff}$ driving the size of the DPS yield. Overall, the discrepancy between theory and experiment may be smaller than expected, which calls for further analyses by ATLAS and CMS, for which we provide predictions, and for full NLO computations in other models. As an interesting side product of our analysis, we have performed the first NLO computation of $d\sigma / dP_T$ for prompt single-$J/\psi$ production in the CEM from which we have fit the CEM non-pertubative parameter at NLO using the most recent ATLAS data.Lansberg, Jean-PhilippeShao, Hua-ShengThu, 11 Aug 2016 09:44:14 GMT10 Aug 2016arXiv:1608.03198http://cds.cern.ch/record/2207118['arXiv:1608.03198']arXiv:1608.03198On gravitational and thermal corrections to vacuum decay
http://cds.cern.ch/record/2206654
We reconsider gravitational corrections to vacuum decay, confirming and simplifying earlier results and extending them allowing for a non-minimal coupling of the Higgs to gravity, finding that leading-order gravitational corrections suppress the vacuum decay rate. Furthermore, we find minor corrections to thermal vacuum decay in the SM adding one-loop corrections to the Higgs kinetic term, two-loop corrections to the Higgs potential and allowing for time-dependent bounces.Salvio, AlbertoStrumia, AlessandroTetradis, NikolaosUrbano, AlfredoWed, 10 Aug 2016 07:19:21 GMT08 Aug 2016arXiv:1608.02555http://cds.cern.ch/record/2206654['arXiv:1608.02555']arXiv:1608.02555Inflation from Supergravity with Gauged R-symmetry in de Sitter Vacuum
http://cds.cern.ch/record/2206494
We study the cosmology of a recent model of supersymmetry breaking, in the presence of a tuneable positive cosmological constant, based on a gauged shift symmetry of a string modulus that can be identified with the string dilaton. The minimal spectrum of the `hidden' supersymmetry breaking sector consists then of a vector multiplet that gauges the shift symmetry of the dilaton multiplet and when coupled to the MSSM leads to a distinct low energy phenomenology depending on one parameter. Here we study the question if this model can also lead to inflation by identifying the dilaton with the inflaton. We find that this is possible if the K\"ahler potential is modified by a term that has the form of NS5-brane instantons, leading to an appropriate inflationary plateau around the maximum of the scalar potential, depending on two extra parameters. This model is consistent with present cosmological observations without modifying the low energy particle phenomenology associated to the minimum of the scalar potential.Antoniadis, IChatrabhuti, AIsono, HKnoops, RWed, 10 Aug 2016 07:14:28 GMT06 Aug 2016arXiv:1608.02121http://cds.cern.ch/record/2206494['arXiv:1608.02121']arXiv:1608.02121Protected couplings and BPS dyons in half-maximal supersymmetric string vacua
http://cds.cern.ch/record/2205505
We analyze four- and six-derivative couplings in the low energy effective action of $D=3$ string vacua with half-maximal supersymmetry. In analogy with an earlier proposal for the $(\nabla\Phi)^4$ coupling, we propose that the $\nabla^2(\nabla\Phi)^4$ coupling is given exactly by a manifestly U-duality invariant genus-two modular integral. In the limit where a circle in the internal torus decompactifies, the $\nabla^2(\nabla\Phi)^4$ coupling reduces to the $D^2 F^4$ and $R^2 F^2$ couplings in $D=4$, along with an infinite series of corrections of order $e^{-R}$, from four-dimensional 1/4-BPS dyons whose wordline winds around the circle. Each of these contributions is weighted by a Fourier coefficient of a meromorphic Siegel modular form, explaining and extending standard results for the BPS index of 1/4-BPS dyons.Bossard, GuillaumeCosnier-Horeau, CharlesPioline, BorisFri, 05 Aug 2016 06:03:23 GMT04 Aug 2016arXiv:1608.01660http://cds.cern.ch/record/2205505['arXiv:1608.01660']arXiv:1608.01660Full mass dependence in Higgs boson production in association with jets at the LHC and FCC
http://cds.cern.ch/record/2205473
The first computation of Higgs production in association with three jets at NLO in QCD has recently been performed using the effective theory, where the top quark is treated as an infinitely heavy particle and integrated out. This approach is restricted to the regions in phase space where the typical scales are not larger than the top quark mass. Here we investigate this statement at a quantitative level by calculating the leading-order contributions to the production of a Standard Model Higgs boson in association with up to three jets taking full top-quark and bottom-quark mass dependence into account. We find that the transverse momentum of the hardest particle or jet plays a key role in the breakdown of the effective theory predictions, and that discrepancies can easily reach an order of magnitude for transverse momenta of about 1 TeV. The impact of bottom-quark loops are found to be visible in the small transverse momentum region, leading to corrections of up to 5 percent. We further study the impact of mass corrections when VBF selection cuts are applied and when the center-of-mass energy is increased to 100 TeV.Greiner, NicolasHoeche, StefanLuisoni, GionataSchonherr, MarekWinter, Jan-ChristopherFri, 05 Aug 2016 06:02:34 GMT03 Aug 2016arXiv:1608.01195http://cds.cern.ch/record/2205473['arXiv:1608.01195']arXiv:1608.01195