Thu·Nov 26, 2015Thursday·November 26, 2015

1. 01*

   Prospects for Higgs physics at energies up to 100 TeV

   Julien Baglio🇩🇪 · Abdelhak Djouadi🇫🇷 · Jérémie Quevillon🇬🇧

   We summarise the prospects for Higgs boson physics at future proton-proton colliders with centre of mass (c.m.) energies up to 100 TeV. We first provide the production cross sections for the Higgs boson of the Standard Model from 13 TeV to 100 TeV, in the main production mechanisms and in subleading but important ones such as double Higgs production, triple production and associated production with two gauge bosons or with a single top quark. We then discuss the production of Higgs particles in beyond the Standard Model scenarios, starting with the one in the continuum of a pair of scalar, fermionic and vector dark matter particles in Higgs-portal models in various channels with virtual Higgs exchange. The cross sections for the production of the heavier CP-even and CP-odd neutral Higgs states and the charged Higgs states in two-Higgs doublet models, with a specific study of the case of the Minimal Supersymmetric Standard Model, are then given. The sensitivity of a 100 TeV proton machine to probe the new Higgs states is discussed and compared to that of the LHC with a c.m. energy of 14 TeV and at high luminosity.

   hep-phhep-exRept.Prog.Phys.(2016)·71 citations
2. 02*

   Approaching Minimal Flavour Violation from an SU(5) x S4 x U(1) SUSY GUT

   Maria Dimou🇬🇧 · Stephen F. King🇬🇧 · Christoph Luhn🇩🇪

   We show how approximate Minimal Flavour Violation (MFV) can emerge from an SU(5) Supersymmetric Grand Unified Theory (SUSY GUT) supplemented by an S4 x U(1) family symmetry, which provides a good description of all quark and lepton (including neutrino) masses, mixings and CP violation. Assuming a SUSY breaking mechanism which respects the family symmetry, we calculate in full explicit detail the low energy mass insertion parameters in the super-CKM basis, including the effects of canonical normalisation and renormalisation group running. We find that the very simple family symmetry S4 x U(1) is sufficient to approximately reproduce the effects of low energy MFV.

   hep-phJHEP(2016)·21 citations
3. 03*

   Fermion mass and mixing pattern in a minimal T7 flavor 331 model

   A. E. Cárcamo Hernández🇨🇱 · R. Martinez🇨🇴

   We present a model based on the $SU(3{)}_C\otimes SU(3{)}_L\otimes U(1{)}_X$ gauge symmetry having an extra $T_7\otimes Z_2\otimes Z_3\otimes Z_{14}$ flavor group, which successfully describes the observed SM fermion mass and mixing pattern. In this framework, the light active neutrino masses arise via double seesaw mechanism and the observed charged fermion mass and quark mixing hierarchy is a consequence of the $Z_2\otimes Z_3\otimes Z_{14}$ symmetry breaking at very high energy. In our minimal $T_7$ flavor 331 model, the spectrum of neutrinos includes very light active neutrinos as well as heavy and very heavy sterile neutrinos. The obtained physical observables for both quark and lepton sectors are compatible with their experimental values. The model predicts the absence of leptonic Dirac CP violating phase.

   hep-phPoS(2015)·8 citations
4. 04*

   Dominant mixed QCD-electroweak $\mathcal{O}({\alpha }_s\alpha )$ corrections to Drell-Yan processes in the resonance region

   Stefan Dittmaier🇩🇪 · Alexander Huss🇨🇭 · Christian Schwinn🇩🇪

   A precise theoretical description of W- and Z-boson production in the resonance region is essential for the correct interpretation of high-precision measurements of the W-boson mass and the effective weak mixing angle. Currently, the largest unknown fixed-order contribution is given by the mixed QCD-electroweak corrections of $\mathcal{O}({\alpha }_s\alpha )$. We argue, using the framework of the pole expansion for the NNLO QCD-electroweak corrections established in a previous paper, that the numerically dominant corrections arise from the combination of large QCD corrections to the production with the large electroweak corrections to the decay of the W/Z boson. We calculate these so-called factorizable corrections of "initial-final" type and estimate the impact on the W-boson mass extraction. We compare our results to simpler approximate combinations of electroweak and QCD corrections in terms of naive products of NLO QCD and electroweak correction factors and using leading-logarithmic approximations for QED final-state radiation as provided by the structure-function approach or QED parton-shower programs. We also compute corrections of "final-final" type, which are given by finite counterterms to the leptonic vectorboson decays and are found to be numerically negligible.

   hep-phNPB(2016)·137 citations
5. 05*

   Consistency check of charged hadron multiplicities and fragmentation functions in SIDIS

   Dong-Jing Yang🇹🇼 · Fu-Jiun Jiang🇹🇼 · Wen-Chen Chang🇹🇼 · Chung-Wen Kao🇹🇼 · Seung-il Nam🇰🇷

   We derived the conditions on certain combinations of integrals of the fragmentation functions of pion using HERMES data of the sum for the charged pion multiplicities from semi-inclusive deep-inelastic scattering (SIDIS) off the deuteron target. In our derivation the nucleon parton distribution functions (PDFs) are assumed to be isospin SU(2) symmetric. Similar conditions have also been obtained for the fragmentation functions (FFs) of kaon by the sum of charged kaon multiplicities as well. We have chosen several FFs to study the impact of those conditions we have derived. Among those FFs, only that produced in the nonlocal chiral-quark model (NL$\chi$QM) constantly satisfy the conditions. Furthermore, the ratios of the strange PDFs $S(x)$ and the nonstrange PDFs $Q(x,Q^2)$ extracted from the charged pion and kaon multiplicities differ from each other significantly. Finally, we demonstrate that the HERMES pion multiplicity data is unlikely to be compatible with the two widely-used PDFs, namely CTEQ6M and NNPDF3.0.

   hep-phhep-exnucl-thPLB(2016)·8 citations
6. 06*

   BSM effects on the Higgs transverse-momentum spectrum in an EFT approach

   Massimiliano Grazzini🇨🇭 · Agnieszka Ilnicka🇨🇭 · Michael Spira🇨🇭 · Marius Wiesemann🇨🇭

   Effective Field Theories offer a consistent bottom-up approach to parametrise small deviations from Standard Model predictions. In this work we report on the application of the Effective Field Theory to shed light on effects from high-scale physics beyond the Standard Model on the Higgs transverse-momentum spectrum. The Standard Model prediction for the transverse-momentum distribution in Higgs boson production through gluon fusion is augmented by three new dimension-six operators, implying the modification of the top and bottom Yukawa couplings, and the inclusion of a point-like Higgs-gluon coupling. We present resummed transverse-momentum spectra including these operators at NLO+NLL accuracy and study their effects on the shape of the distribution. The proper parametrization of such effects becomes increasingly important for experimental analyses in Run II of the LHC.

   hep-phPoS(2015)·8 citations
7. 07*

   Heavy to light Higgs boson decays at NLO in the Singlet Extension of the Standard Model

   F. Bojarski🇫🇷 · G. Chalons🇫🇷 · D. Lopez-Val🇧🇪 · T. Robens🇩🇪

   We study the decay of a heavy Higgs boson into a light Higgs pair at one loop in the singlet extension of the Standard Model. To this purpose, we construct several renormalization schemes for the extended Higgs sector of the model. We apply these schemes to calculate the heavy-to-light Higgs decay width at next-to-leading order electroweak accuracy, and demonstrate that certain prescriptions lead to gauge-dependent results. We comprehensively examine how the NLO predictions depend on the relevant singlet model parameters, with emphasis on the trademark behavior of the quantum effects, and how these change under different renormalization schemes and a variable renormalization scale. Once all present constraints on the model are included, we find mild NLO corrections, typically of few percent, and with small theoretical uncertainties.

   hep-phJHEP(2016)·70 citations
8. 08*

   High-scale validity of a model with Three-Higgs-doublets

   Nabarun Chakrabarty🇮🇳

   We consider a three-Higgs doublet scenario in this paper, invariant under the discrete group S3 , and probe its high-scale validity by allowing the model parameters to evolve under a renormalization group. We choose two particular alignments of vacuum expectation values (vev) for our study, out of a set of several such possible ones. All three doublets receive nonzero vacuum expectation values in the first case, and in the second case, two of the doublets remain without vev. The constraints on the parameter space at low energy, including the measured value of the Higgs mass and the signal strengths, oblique corrections and also measurements of relic density and direct detection rates are juxtaposed with the conditions of vacuum stability, perturbativity and unitarity at various scales. We find that the scenario with three nonzero vevs is not valid beyond 107 GeV, assuming no additional physics participates at the intermediate scales. On the contrary, the scenario with only one nonzero vev turns out to be a successful model for cold dark matter phenomenology, which also turns out to be valid up to the Planck scale at the same time. Stringent restrictions are obtained on the model parameter space in each case. Thus, the S3 symmetric scalar sector emerges as an ultraviolet complete theory.

   hep-phPRD(2016)·19 citations
9. 09*

   Finite-Dimensional Lie Algebras and Their Representations for Unified Model Building

   Naoki Yamatsu🇯🇵

   We give information about finite-dimensional Lie algebras and their representations for model building in 4 and 5 dimensions; e.g., conjugacy classes, types of representations, Weyl dimensional formulas, Dynkin indices, quadratic Casimir invariants, anomaly coefficients, projection matrices, and branching rules of Lie algebras and their subalgebras up to rank-20. We show what kind of Lie algebras can be applied for grand unified theories in 4 and 5 dimensions.

   hep-phhep-th133 citations
10. 10*

    Non-Minimally Coupled Inflation with Initial Conditions from a Pre-Inflation Anamorphic Contracting Era

    John McDonald🇬🇧

    Inflation due to a non-minimally coupled scalar field with a large non-minimal coupling, as first proposed by Salopek, Bardeen and Bond (SBB), is in good agreement with the observed value of the spectral index and constraints on the tensor-to-scalar ratio. Here we explore the possibility that SBB inflation represents the late stage of a Universe which emerges from an early contracting era. We present a model in which the Universe smoothly transitions from an anamorphic contracting era to late-time SBB inflation without encountering a singular bounce. This corresponds to a continuous expansion in the Einstein frame throughout. We show that the anamorphic contracting era is able to provide the smooth superhorizon initial conditions necessary for subsequent SBB inflation to occur. The model predicts corrections to the non-minimal coupling, kinetic term and potential of SBB inflation which can observably increase the observed spectral index relative to its SBB prediction.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2016)·3 citations
11. 11*

    Single-step de Sitter vacua from non-perturbative effects with matter

    Adolfo Guarino🇳🇱 · Gianluca Inverso🇳🇱

    A scenario of moduli stabilisation based on the interplay between closed and open string sectors is explored in a bottom-up approach. We study N=1 effective supergravities inspired by type IIB orientifold constructions that include background fluxes and non-perturbative effects. The former generate the standard flux superpotential for the axiodilaton and complex structure moduli. The latter can be induced by gaugino condensation in a non-Abelian sector of D7-branes and involve the overall Kaehler modulus of the compactification as well as matter fields. We analyse the dynamics of this coupled system and show that it is compatible with single-step moduli stabilisation in a metastable de Sitter vacuum. A novelty of the scenario is that the F-term potential suffices to generate a positive cosmological constant and to stabilise all moduli, except for a flat direction that can be either lifted by a mass term or eaten up by an anomalous U(1).

    ↳ hep-thhep-phPRD(2016)·6 citations
12. 12*

    SOLARPROP: Charge-sign Dependent Solar Modulation for Everyone

    Rolf Kappl🇩🇪

    We present SOLARPROP, a tool to compute the influence of charge-sign dependent solar modulation for cosmic ray spectra. SOLARPROP is able to use the output of popular tools like GALPROP or DRAGON and offers the possibility to embed new models for solar modulation. We present some examples for proton, antiproton and positron fluxes in the light of the recent PAMELA and AMS-02 data.

    ↳ astro-ph.SRastro-ph.HEastro-ph.IMhep-ph+1Comput.Phys.Commun.(2016)·53 citations
13. 13*

    Why is High Energy Physics Lorentz Invariant?

    Niayesh Afshordi (Perimeter/Waterloo)🇨🇦

    Despite the tremendous empirical success of equivalence principle, there are several theoretical motivations for existence of a preferred reference frame (or aether) in a consistent theory of quantum gravity. However, if quantum gravity had a preferred reference frame, why would high energy processes enjoy such a high degree of Lorentz symmetry? While this is often considered as an argument against aether, here I provide three independent arguments for why perturbative unitarity (or weak coupling) of the Lorentz-violating effective field theories put stringent constraints on possible observable violations of Lorentz symmetry at high energies. In particular, the interaction with the scalar graviton in a consistent low-energy theory of gravity and a (radiatively and dynamically) stable cosmological framework, leads to these constraints. The violation (quantified by the relative difference in maximum speed of propagation) is limited to $\lesssim 10^{-10}E(\mathrm{eV}{)}^{-4}$ (superseding all current empirical bounds), or the theory will be strongly coupled beyond meV scale. The latter happens in extended Horava-Lifshitz gravities, as a result of a previously ignored quantum anomaly. Finally, given that all cosmologically viable theories with significant Lorentz violation appear to be strongly coupled beyond meV scale, we conjecture that, similar to color confinement in QCD, or Vainshetin screening for massive gravity, high energy theories (that interact with gravity) are shielded from Lorentz violation (at least, up to the scale where gravity is UV-completed). In contrast, microwave or radio photons, cosmic background neutrinos, or gravitational waves may provide more promising candidates for discovery of violations of Lorentz symmetry.

    ↳ hep-thastro-ph.COgr-qchep-ph10 citations
14. 14*

    Freeze-out conditions for production of resonances, hadronic molecules, and light nuclei

    Sungtae Cho🇰🇷 · Taesoo Song🇩🇪 · Su Houng Lee🇰🇷

    We investigate the freeze-out conditions of a particle in an expanding system of interacting particles in order to understand the productions of resonances, hadronic molecules and light nuclei in heavy ion collisions. Applying the kinetic freeze-out condition with explicit hydrodynamic calculations for the expanding hadronic phase to the daughter particles of $K^{\ast }$ mesons, we find that the larger suppression of the yield ratio of $K^{\ast }/K$ at LHC than at RHIC compared to the expectations from the statistical hadronization model based on chemical freeze-out parameters reflects the lower kinetic freeze-out temperature at LHC than at RHIC. Furthermore, we point out that for the light nuclei or hadronic molecules that are bound, the yields are affected by the freeze-out condition of the respective particle in the hadronic matter, which leads to the observation that the deuteron production yields are independent of the size of deuteron, and depend only on the number of ground state constituents.

    ↳ nucl-thhep-exhep-phPRC(2018)·13 citations
15. 15*

    Conformal Collider Physics from the Lightcone Bootstrap

    Daliang Li🇺🇸 · David Meltzer🇺🇸 · David Poland🇺🇸

    We analytically study the lightcone limit of the conformal bootstrap equations for 4-point functions containing global symmetry currents and the stress tensor in 3d CFTs. We show that the contribution of the stress tensor to the anomalous dimensions of large spin double-twist states is negative if and only if the conformal collider physics bounds are satisfied. In the context of AdS/CFT these results indicate a relation between the attractiveness of AdS gravity and positivity of the CFT energy flux. We also study the contribution of non-Abelian conserved currents to the anomalous dimensions of double-twist operators, corresponding to the gauge binding energy of 2-particle states in AdS. We show that the representation of the double-twist state determines the sign of the gauge binding energy if and only if the coefficient appearing in the current 3-point function satisfies a similar bound, which is equivalent to an upper bound on the charge flux asymmetry of the CFT.

    ↳ hep-thhep-phJHEP(2016)·83 citations
16. 16*

    Critical take on "Mass models of disk galaxies from the DiskMass Survey in MOND"

    Mordehai Milgrom🇮🇱

    Angus et al. (2015) have recently faulted MOND as follows: Studying thirty disc galaxies from the DiskMass survey, they derive the profiles of velocity dispersion perpendicular to the discs as predicted by MOND, ${\sigma }_M(r)$, and compare them with $\sigma (r)$, measured as part of the DiskMass project. This is a new test of MOND, different from rotation-curve analysis. A nontrivial accomplishment of MOND -- not discussed by Angus et al. -- is that the shapes of ${\sigma }_M$ and $\sigma$ agree very well, i.e, $\eta (r)\equiv {\sigma }_M(r)/\sigma (r)$ is well consistent with being $r$-independent (while $\sigma$ and ${\sigma }_M$ are strongly $r$ dependent). The fault found with MOND was that $\eta$ is systematically above 1 (with an average of about 1.3). I have suggested to Angus et al. that the fault may lie with the DiskMass dispersions, which may well be too low for the purpose at hand: Being based on population-integrated line profiles, they may be overweighed by younger populations, known to have much smaller dispersions, and scale heights, than the older populations, which weigh more heavily on the light distributions. I discuss independent evidence that supports this view, and show, besides, that if the DiskMas dispersions are underestimates by only 25 %, on average, the MOND predictions are in full agreement with the data, in shape and magnitude. Now, Aniyan et al. (2015) have questioned the DiskMass $\sigma$ on the same basis. They show for the solar column in the Milky Way that: " Combining the (single) measured velocity dispersion of the total young + old disc population... with the scale height estimated for the older population would underestimate the disc surface density by a factor of $\sim 2.$" If this mismatch found for the Milky Way is typical, correcting for it would bring the measured DiskMass $\sigma (r)$ to a remarkable agreement with the predicted MOND ${\sigma }_M(r)$.

    ↳ astro-ph.GAgr-qchep-ph6 citations
17. 17*

    Moduli Stabilisation with Nilpotent Goldstino: Vacuum Structure and SUSY Breaking

    Luis Aparicio🇮🇹 · Fernando Quevedo🇮🇹 · Roberto Valandro🇮🇹

    We study the effective field theory of KKLT and LVS moduli stabilisation scenarios coupled to an anti-D3-brane at the tip of a warped throat. We describe the presence of the anti-brane in terms of a nilpotent goldstino superfield in a supersymmetric effective field theory. The introduction of this superfield produces a term that can lead to a de Sitter minimum. We fix the Kaehler moduli dependence of the nilpotent field couplings by matching this term with the anti-D3-brane uplifting contribution. The main result of this paper is the computation, within this EFT, of the soft supersymmetry breaking terms in both KKLT and LVS for matter living on D3-brane (leaving the D7-brane analysis to an appendix). A handful of distinct phenomenological scenarios emerge that could have low energy implications, most of them having a split spectrum of soft masses. Some cosmological and phenomenological properties of these models are discussed. We also check that the attraction between the D3-brane and the anti-D3-brane does not affect the leading contribution to the soft masses and does not destabilise the system.

    ↳ hep-thhep-phJHEP(2016)·63 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.