Fri·Dec 25, 2015Friday·December 25, 2015

1. 01*

   $W^{+}{W}^{-}$ + 3 Jet Production at the Large Hadron Collider in NLO QCD

   F. Febres Cordero🇩🇪 · P. Hofmann🇩🇪 · H. Ita🇩🇪

   We present next-to-leading order (NLO) QCD predictions to $W^{+}{W}^{-}$ production in association with up to three jets at hadron colliders. We include contributions from couplings of the $W$ bosons to light quarks as well as trilinear vector couplings. These processes are used in vector-boson coupling measurements, are background to Higgs signals and are needed to constrain many new physics scenarios. For the first time NLO QCD predictions are shown for electroweak di-vector boson production with three jets at a hadron collider. We show total and differential cross sections for the LHC with proton center-of-mass energies of 8 and 13 TeV. To perform the calculation we employ on-shell and unitarity methods implemented in the BlackHat library along with the SHERPA package. We have produced event files that can be accessed for future dedicated studies.

   hep-phhep-exPRD(2017)·14 citations
2. 02*

   On the 750 GeV di-photon excess

   Wolfgang Altmannshofer🇨🇦 · Jamison Galloway🇺🇸 · Stefania Gori🇨🇦 · Alexander L. Kagan🇺🇸 · Adam Martin🇺🇸 · Jure Zupan🇺🇸

   We explore several perturbative scenarios in which the di-photon excess at 750 GeV can potentially be explained: a scalar singlet, a two Higgs doublet model (2HDM), a 2HDM with an extra singlet, and the decays of heavier resonances, both vector and scalar. We draw the following conclusions: (i) due to gauge invariance a 750 GeV scalar singlet can accommodate the observed excess more readily than a scalar SU(2)_L doublet; (ii) scalar singlet production via gluon fusion is one option, however, vector boson fusion can also provide a large enough rate, (iii) 2HDMs with an extra singlet and no extra fermions can only give a signal in a severely tuned region of the parameter space; (iv) decays of heavier resonances can give a large enough di-photon signal at 750 GeV, while simultaneously explaining the absence of a signal at 8 TeV.

   hep-phPRD(2016)·133 citations
3. 03*

   String Consistency, Heavy Exotics, and the $750$ GeV Diphoton Excess at the LHC

   Mirjam Cvetič🇺🇸 · James Halverson🇺🇸 · Paul Langacker🇺🇸

   String consistency conditions are stronger than anomaly cancellation and can require the addition of exotics in the visible sector. We study such exotics and demonstrate that they may account for the modest excess at $750$ GeV in recent diphoton resonance searches performed by the ATLAS and CMS collaborations. In a previous analysis of type II MSSM D-brane quivers we systematically added up to five exotics for the sake of satisfying string consistency conditions. Using this dataset, we demonstrate that 89780 of the 89964 quivers have exotics, 78155 of which include singlets that may couple to MSSM or exotic multiplets with coupling structures governed by $U(1)$ symmetries that are often anomalous. We demonstrate that certain sets of exotics are far preferred over others and study the structure of singlet couplings to heavy exotics carrying standard model charges. Typical possibilities include singlets that may decay to vector-like quarks and / or vector-like leptons and subsequently to two photons. We show that a narrow width diphoton excess can be accounted for while evading existing bounds if multiple exotics are added, with vector-like leptons of mass $M_L\lesssim 375$ GeV and vector-like quarks with masses up to $\simeq 3$ TeV. However, a large width $(\Gamma /M\sim 0.06)$, as suggested by the ATLAS data, cannot be easily accommodated in this framework. Renormalization group equations with GUT-scale boundary conditions show that these supersymmetric models are perturbative and stable. Type IIA compactifications on toroidal orbifolds allow for $O(10)$ Yukawa couplings in the ultraviolet. We also discuss the possibility of accounting for the diphoton excess in a low string scale scenario via the decay of string axions.

   hep-phhep-exhep-thFortsch.Phys.(2016)·111 citations
4. 04*

   Running after Diphoton

   Jiayin Gu🇨🇳 · Zhen Liu🇺🇸

   A very plausible explanation for the recently observed diphoton excess at the 13 TeV LHC is a (pseudo)scalar with mass around 750 GeV, which couples to a gluon pair and to a photon pair through loops involving vector-like quarks (VLQs). To accommodate the observed rate, the required Yukawa couplings tend to be large. A large Yukawa coupling would rapidly run up with the scale and quickly reach the perturbativity bound, indicating that new physics, possibly with a strong dynamics origin, is near by. The case becomes stronger especially if the ATLAS observation of a large width persists. In this paper we study the implication on the scale of new physics from the 750 GeV diphoton excess using the method of renormalization group running with careful treatment of different contributions and perturbativity criterion. Our results suggest that the scale of new physics is generically not much larger than the TeV scale, in particular if the width of the hinted (pseudo)scalar is large. Introducing multiple copies of VLQs, lowing the VLQ masses and enlarging VLQ electric charges help reduce the required Yukawa couplings and can push the cutoff scale to higher values. Nevertheless, if the width of the 750 GeV resonance turns out to be larger than about 1 GeV, it is very hard to increase the cutoff scale beyond a few TeVs. This is a strong hint that new particles in addition to the 750 GeV resonance and the vector-like quarks should be around the TeV scale.

   hep-phhep-exPRD(2016)·98 citations
5. 05*

   Di-photon Excess Explained by a Resonant Sneutrino in R-parity Violating Supersymmetry

   B. C. Allanach🇬🇧 · P. S. Bhupal Dev🇩🇪 · S. A. Renner🇬🇧 · Kazuki Sakurai🇬🇧

   We explain the recent excess seen by ATLAS and CMS experiments at around 750 GeV in the di-photon invariant mass as a narrow width sneutrino decaying to di-photons via a stau loop in R-parity violating Supersymmetry. The stau mass is predicted to be somewhere between half the resonant sneutrino mass and half the sneutrino mass plus 14 GeV. The scenario also predicts further signal channels at an invariant mass of 750 GeV, the most promising being into di-jets and $WW$. We also predict a left handed charged slepton decaying into $WZ$ and $W\gamma$ at a mass 750-754 GeV.

   hep-phhep-exPRD(2016)·116 citations
6. 06*

   A 750 GeV Messenger of Dark Conformal Symmetry Breaking

   Hooman Davoudiasl🇺🇸 · Cen Zhang🇺🇸

   The tentative hints for a diphoton resonance at a mass of $\sim 750$ GeV from the ATLAS and CMS experiments at the LHC may be interpreted as first contact with a "dark" sector with a spontaneously broken conformal symmetry. The implied TeV scale of the dark sector may be motivated by the interaction strength required to accommodate a viable thermal relic dark matter (DM) candidate. We model the conformal dynamics using a Randall-Sundrum type 5D geometry whose IR boundary is identified with the dynamics of the composite dark sector, while the Standard Model (SM) matter content resides on the UV boundary, corresponding to "elementary" fields. We allow the gauge fields to reside in the 5D bulk, which can be minimally chosen to be $SU(3{)}_c\times U(1{)}_Y$. The "dark" radion is identified as the putative 750 GeV resonance. Heavy vector-like fermions, often invoked to explain the diphoton excess, are not explicitly present in our model and are not predicted to appear in the spectrum of TeV scale states. Our minimal setup favors scalar DM of $\mathcal{O}(\text{TeV})$ mass. A generic expectation in this scenario, suggested by DM considerations, is the appearance of vector bosons at $\sim$ few TeV, corresponding to the gluon and hypercharge Kaluza-Klein (KK) modes that couple to UV boundary states with strengths that are suppressed uniformly compared to their SM values. Our analysis suggests that these KK modes could be within the reach of the LHC in the coming years.

   hep-phhep-exPRD(2016)·94 citations
7. 07*

   Phenomenology of the new physics coming from 2HDMs to the neutrino magnetic dipole moment

   Carlos G. Tarazona🇨🇴 · Rodolfo A. Diaz🇨🇴 · John Morales🇨🇴 · Andres Castillo🇨🇴

   In several frameworks for leptons-sectors of two Higgs doublet models, we calculate the magnetic dipole moment for the different flavor types of neutrino. Computations are carried out by assuming a normal hierarchy for neutrino masses, and analyzing the process $\nu \to \nu \gamma$ with a charged Higgs boson into the loop. The analysis was performed by sweeping the charged Higgs mass and taking into account the experimental constraints for relevant parameters in Two Higgs Doublet Models with and without flavor changing neutral currents; obtaining magnetic dipole moments close to the experimental thresholds for tau neutrinos in type II and Lepton-specific cases. In the neutrino-specific scenario, the contribution of new physics could be sizeable to the current measurement for flavor magnetic dipole moment. This fact leads to excluding possible zones in the parameter space of charged Higgs mass and vacuum expectation value of the second doublet.

   hep-phInt.J.Mod.Phys.A(2017)·3 citations
8. 08*

   Shedding Light on Diphoton Resonances

   Nathaniel Craig🇺🇸 · Patrick Draper🇺🇸 · Can Kilic🇺🇸 · Scott Thomas🇺🇸

   The experimental and theoretical implications of heavy digauge boson resonances that couple to, or are comprised of, new charged and strongly interacting matter are investigated. Observation and measurement of ratios of the resonant digauge boson channels $WW$, $ZZ$, $\gamma \gamma$, $Z\gamma$, and $gg$ in the form of dijets, provide a rather direct -- and for some ratios a rather robust -- probe of the gauge representations of the new matter. For a spin-zero resonance with the quantum numbers of the vacuum, the ratios of resonant $WW$ and $ZZ$ to $\gamma \gamma$ channels, as well as the longitudinal versus transverse polarization fractions in the $WW$ and $ZZ$ channels, provide probes for possible mixing with the Higgs boson, while di-Higgs and ditop resonant channels, $hh$ and $tt$, provide somewhat less sensitivity. We present a survey of possible underlying models for digauge boson resonances by considering various limits for the mass of the new charged and strongly interacting matter fields as well as the confinement scale of new hypergauge interactions under which they may also be charged. In these limits, resonances may be included as elementary weakly coupled spin-zero states or can correspond to hyperglueballs, hyperonia, or pseudoscalar hypermesons. For each of these cases, we make predictions for additional states that could be resonantly or pair produced and observed at the Large Hadron Collider or in future collider experiments. Heavy digauge boson resonances can provide a unified explanation for a number of small discrepancies and excesses in reported data from the Large Hadron Collider.

   hep-phPRD(2016)·103 citations
9. 09*

   Vacuum stability and supersymmetry at high scales with two Higgs doublets

   Emanuele Bagnaschi🇩🇪 · Felix Brümmer🇫🇷 · Wilfried Buchmüller🇩🇪 · Alexander Voigt🇩🇪 · Georg Weiglein🇩🇪

   We investigate the stability of the electroweak vacuum for two-Higgs doublet models with a supersymmetric UV completion. The supersymmetry breaking scale is taken to be of the order of the grand unification scale. We first study the case where all superpartners decouple at this scale. We show that contrary to the Standard Model with one Higgs doublet, matching to the supersymmetric UV completion is possible if the low-scale model contains two Higgs doublets. In this case vacuum stability and experimental constraints point towards low values of tan(beta) < 2 and pseudoscalar masses of at least about a TeV. If the higgsino superpartners of the Higgs fields are also kept light, the conclusions are similar and essentially independent of the higgsino mass. Finally, if all gauginos are also given electroweak-scale masses (split supersymmetry with two Higgs doublets), the model cannot be matched to supersymmetry at very high scales when requiring a 125 GeV Higgs. Light neutral and charged higgsinos therefore emerge as a promising signature of a supersymmetric UV completion of the Standard Model at the grand unification scale.

   hep-phJHEP(2016)·54 citations
10. 10*

    The 750 GeV Diphoton excess in a $U(1)$ hidden symmetry model

    Kasinath Das🇮🇳 · Santosh Kumar Rai🇮🇳

    Recent results from the experimental collaborations at LHC give hints of a resonance in the diphoton channel at an invariant mass of 750 GeV. We show that such a scalar resonance would be possible in an $U(1)$ extension of the SM where the extended symmetry is hidden and yet to be discovered. We explore the possibilities of accommodating this excess by introducing a minimal extension to the matter content and highlight the parameter space that can accommodate the observed diphoton resonance in the model. The model also predicts new interesting signals that may be observed at the current LHC run.

    hep-phhep-exPRD(2016)·100 citations
11. 11*

    New decay modes of heavy Higgs bosons in a two Higgs doublet model with vectorlike leptons

    Radovan Dermisek🇺🇸 · Enrico Lunghi🇺🇸 · Seodong Shin🇺🇸

    In models with extended Higgs sector and additional matter fields, the decay modes of heavy Higgs bosons can be dominated by cascade decays through the new fermions rendering present search strategies ineffective. We investigate new decay topologies of heavy neutral Higgses in two Higgs doublet model with vectorlike leptons. We also discuss constraints from existing searches and discovery prospects. Among the most interesting signatures are monojet, mono Z, mono Higgs, and Z and Higgs bosons produced with a pair of charged leptons.

    hep-phhep-exJHEP(2016)·30 citations
12. 12*

    Higgs precision study of the 750 GeV diphoton resonance and the 125 GeV standard model Higgs boson with Higgs-singlet mixing

    Kingman Cheung🇹🇼 · P. Ko🇰🇷 · Jae Sik Lee🇰🇷 · Jubin Park🇰🇷 · Po-Yan Tseng🇹🇼

    We interpret the potential observation of the 750 GeV di-photon resonance at the LHC in models, in which an $SU(2)$ isospin-singlet scalar boson mixes with the Standard Model (SM) Higgs boson through an angle $\alpha$. Allowing the singlet scalar boson to have renormalizable couplings to vector-like leptons and quarks and introducing sizable decay width of the 750 GeV di-photon resonance into non-SM particles such as dark matters, we can explain the large production cross section $\sigma (H_2)\times B(H_2\to \gamma \gamma )$ as well as the apparent large total width of the boson without conflicts from the results obtained by previous global fits to the SM Higgs boson data.

    hep-phhep-exPRD(2016)·103 citations
13. 13*

    Theory Motivation For Exotic Signatures: Prospects and Wishlist for Run II

    Daniel Stolarski🇨🇭

    Here I give some motivations for exotic signatures to search for at Run II of the LHC, focusing on displaced phenomena. I will discuss signatures arising from various different kinds of models including theories of dark matter and those with exotic decays of the Higgs.

    hep-phhep-ex0 citations
14. 14*

    Golden Probe of the Top Yukawa

    Yi Chen🇺🇸 · Daniel Stolarski🇨🇭 · Roberto Vega-Morales🇪🇸

    We describe how the Higgs decay to four leptons can be used to probe the nature and $CP$ structure of the top Yukawa coupling.

    hep-phhep-ex0 citations
15. 15*

    Resonance model for non-perturbative inputs to gluon distributions in the hadrons

    B.I. Ermolaev🇷🇺 · F. Olness🇺🇸 · S.I. Troyan🇷🇺

    We construct non-perturbative inputs for the elastic gluon-hadron scattering amplitudes in the forward kinematic region for both polarized and non-polarized hadrons. We use the optical theorem to relate invariant scattering amplitudes to the gluon distributions in the hadrons. By analyzing the structure of the UV and IR divergences, we can determine theoretical conditions on the non-perturbative inputs, and use these to construct the results in a generalized Basic Factorization framework using a simple Resonance Model. These results can then be related to the K_T and Collinear Factorization expressions, and the corresponding constrains can be extracted.

    hep-ph0 citations
16. 16*

    Non-Gaussian Covariance of the Matter Power Spectrum in the Effective Field Theory of Large Scale Structure

    Daniele Bertolini🇺🇸 · Katelin Schutz🇺🇸 · Mikhail P. Solon🇺🇸 · Jonathan R. Walsh🇺🇸 · Kathryn M. Zurek🇺🇸

    We compute the non-Gaussian contribution to the covariance of the matter power spectrum at one-loop order in Standard Perturbation Theory (SPT), and using the framework of the effective field theory (EFT) of large scale structure (LSS). The complete one-loop contributions are evaluated for the first time, including the leading EFT corrections that involve seven independent operators, of which four appear in the power spectrum and bispectrum. We compare the non-Gaussian part of the one-loop covariance computed with both SPT and EFT of LSS to two separate simulations. In one simulation, we find that the one-loop prediction from SPT reproduces the simulation well to $k_i+k_j\sim$ 0.25 h/Mpc, while in the other simulation we find a substantial improvement of EFT of LSS (with one free parameter) over SPT, more than doubling the range of $k$ where the theory accurately reproduces the simulation. The disagreement between these two simulations points to unaccounted for systematics, highlighting the need for improved numerical and analytic understanding of the covariance.

    ↳ astro-ph.COhep-phPRD(2016)·85 citations
17. 17*

    Quantum Gravitational Force Between Polarizable Objects

    L. H. Ford🇺🇸 · Mark P. Hertzberg🇺🇸 · J. Karouby🇺🇸

    Since general relativity is a consistent low energy effective field theory, it is possible to compute quantum corrections to classical forces. Here we compute a quantum correction to the gravitational potential between a pair of polarizable objects. We study two distant bodies and compute a quantum force from their induced quadrupole moments due to two graviton exchange. The effect is in close analogy to the Casimir-Polder and London-van der Waals forces between a pair of atoms from their induced dipole moments due to two photon exchange. The new effect is computed from the shift in vacuum energy of metric fluctuations due to the polarizability of the objects. We compute the potential energy at arbitrary distances compared to the wavelengths in the system, including the far and near regimes. In the far distance, or retarded, regime, the potential energy takes on a particularly simple form: $V(r)=-3987\hslash c{G}^2{\alpha }_{1S}{\alpha }_{2S}/(4\pi r^{11})$, where ${\alpha }_{1S},{\alpha }_{2S}$ are the static gravitational quadrupole polarizabilities of each object. We provide estimates of this effect.

    ↳ hep-thastro-ph.COgr-qchep-ph+1PRL(2016)·34 citations
18. 18*

    Hypernuclei in Halo/Cluster Effective Field Theory

    Shung-Ichi Ando (Sunmoon U.)🇰🇷

    The light double $\Lambda$ hypernuclei, ${}_{\Lambda \Lambda }^4$H and ${}_{\Lambda \Lambda }^6$He, are studied as three-body $\Lambda \Lambda d$ and $\Lambda \Lambda \alpha$ cluster systems in halo/cluster effective field theory at leading order. We find that the $\Lambda \Lambda d$ system in spin-0 channel does not exhibit a limit cycle whereas the $\Lambda \Lambda d$ system in spin-1 channel and the $\Lambda \Lambda \alpha$ system in spin-0 channel do. The limit cycle is associated with the formation of bound states, known as Efimov states, in the unitary limit. For the $\Lambda \Lambda d$ system in the spin-0 channel we estimate the scattering length $a_0$ for $S$-wave $\Lambda$ hyperon-hypertriton scattering as $a_0=16.0\pm 3.0$ fm. We also discuss that studying the cutoff dependences in the $\Lambda \Lambda d$ and $\Lambda \Lambda \alpha$ systems, the bound state of ${}_{\Lambda \Lambda }^4$H is not an Efimov state but formed due to a high energy mechanism whereas that of ${}_{\Lambda \Lambda }^6$He may be regarded as an Efimov state.

    ↳ nucl-thhep-phnucl-exIJMPE(2016)·8 citations
19. 19*

    Genus one super-Green function revisited and superstring amplitudes with non-maximal supersymmetry

    H. Itoyama🇯🇵 · Kohei Yano🇯🇵

    We reexamine genus one super-Green functions with general boundary conditions twisted by $(\alpha ,\beta )$ for $(\sigma ,\tau )$ directions in the eigenmode expansion and derive expressions as infinite series of hypergeometric functions. Using these, we compute one-loop superstring amplitudes with non-maximal supersymmetry, taking an example of massless vector emissions of open string type I ${\mathcal{Z}}_2$ orbifold.

    ↳ hep-thhep-phPTEP(2016)·2 citations
20. 20*

    Numerical forecasts for lab experiments constraining modified gravity: the chameleon model

    Sandrine Schlogel🇧🇪 · Sebastien Clesse🇧🇪 · Andre Fuzfa🇧🇪

    Current acceleration of the cosmic expansion leads to coincidence as well as fine-tuning issues in the framework of general relativity. Dynamical scalar fields have been introduced in response of these problems, some of them invoking screening mechanisms for passing local tests of gravity. Recent lab experiments based on atom interferometry in a vacuum chamber have been proposed for testing modified gravity models. So far only analytical computations have been used to provide forecasts. We derive numerical solutions for chameleon models that take into account the effect of the vacuum chamber wall and its environment. With this realistic profile of the chameleon field in the chamber, we refine the forecasts that were derived analytically. We finally highlight specific effects due to the vacuum chamber that are potentially interesting for future experiments.

    ↳ astro-ph.COhep-ph2 citations
21. 21*

    Inflation model constraints from data released in 2015

    Qing-Guo Huang🇨🇳 · Ke Wang🇨🇳 · Sai Wang🇨🇳

    We provide the latest constraints on the power spectra of both scalar and tensor perturbations from the CMB data (including \textit{Planck}~2015, BICEP2 \& \textit{Keck Array} experiments) and the new BAO scales from SDSS-III BOSS observation. We find that the inflation model with a convex potential is not favored and both the inflation model with a monomial potential and the natural inflation model are marginally disfavored at around $95\%$ confidence level. But both the Brane inflation model and the Starobinsky inflation model fit the data quite well.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2016)·52 citations
22. 22*

    Use of the Meta-analysis and Kolmogorov Criteria in the Finding of Singularities of a Nuclear Matter Created in Ultra Relativistic Nuclear Collisions

    V.A. Kizka🇺🇦

    Published theoretical data from several models: PHSD and HSD both with and without chiral symmetry restoration (CSR), applied to experimental data on nuclear collisions from BEVALAC and SIS to LHC energies were analyzed using meta-analysis and Kolmogorov criteria. This made it possible to localize possible features of nuclear matter created in central nucleus-nucleus collisions. Ignition of a drop of quark-gluon plasma (QGP) begins already at an energy of about $\sqrt{s_{NN}}$ = 2 GeV. We estimate that this QGP droplet occupies a small fraction, 15 $\%$ (average radius of about 5.3 fermi if the fireball radius is 10 fermi) of the total volume of the fireball created at $\sqrt{s_{NN}}$ = 2.7 GeV. A drop of exotic matter undergoes a split phase transition: separated boundaries of sharp (1st order) crossover and CSR in chiral limit, between QGP and Quarkyonic matter at an energy about $\sqrt{s_{NN}}$ = 3.5 GeV. The critical endpoint of 2nd order probably cannot be reached in nuclear collisions. The triple phase area occupies interval from $\sqrt{s_{NN}}$ = 12 GeV to 15 GeV, the critical endpoint of 1st order at around $\sqrt{s_{NN}}$ = 20 GeV. The boundary of smooth (2nd order) crossover transition with CSR in chiral limit between Quarkyonic matter and QGP was localized between $\sqrt{s_{NN}}$ = 9.3 GeV and 12 GeV, and between Hadronic and QGP in the interval from $\sqrt{s_{NN}}$ = 15 GeV to 20 GeV, the boundary of sharp (1st order) crossover transition with CSR in chiral limit between Hadronic matter and QGP was localized after $\sqrt{s_{NN}}$ = 20 GeV. The phase trajectory of the hadronic corona, enveloping the exotic droplet, always remains in the hadronic phase.

    ↳ nucl-thastro-ph.HEhep-phnucl-exScience(2024)·1 citation

* 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.