Fri·Nov 18, 2016Friday·November 18, 2016

1. 01*

   Perturbative Higgs CP violation, unitarity and phenomenology

   Christoph Englert🇬🇧 · Karl Nordström🇬🇧 · Kazuki Sakurai🇬🇧 · Michael Spannowsky🇬🇧

   Perturbative probability conservation provides a strong constraint on the presence of new interactions of the Higgs boson. In this work we consider CP violating Higgs interactions in conjunction with unitarity constraints in the gauge-Higgs and fermion-Higgs sectors. Injecting signal strength measurements of the recently discovered Higgs boson allows us to make concrete and correlated predictions of how CP-violation in the Higgs sector can be directly constrained through collider searches for either characteristic new states or tell-tale enhancements in multi-Higgs processes.

   hep-phhep-exPRD(2017)·9 citations
2. 02*

   Signatures of Earth-scattering in the direct detection of Dark Matter

   Bradley J. Kavanagh🇫🇷 · Riccardo Catena🇸🇪 · Chris Kouvaris🇩🇰

   Direct detection experiments search for the interactions of Dark Matter (DM) particles with nuclei in terrestrial detectors. But if these interactions are sufficiently strong, DM particles may scatter in the Earth, affecting their distribution in the lab. We present a new analytic calculation of this `Earth-scattering' effect in the regime where DM particles scatter at most once before reaching the detector. We perform the calculation self-consistently, taking into account not only those particles which are scattered away from the detector, but also those particles which are deflected towards the detector. Taking into account a realistic model of the Earth and allowing for a range of DM-nucleon interactions, we present the EarthShadow code, which we make publicly available, for calculating the DM velocity distribution after Earth-scattering. Focusing on low-mass DM, we find that Earth-scattering reduces the direct detection rate at certain detector locations while increasing the rate in others. The Earth's rotation induces a daily modulation in the rate, which we find to be highly sensitive to the detector latitude and to the form of the DM-nucleon interaction. These distinctive signatures would allow us to unambiguously detect DM and perhaps even identify its interactions in regions of the parameter space within the reach of current and future experiments.

   hep-phastro-ph.COJCAP(2017)·83 citations
3. 03*

   Higgs Boson Decay to Light Jets at the LHC

   Linda M. Carpenter🇺🇸 · Tao Han🇺🇸 · Khalida Hendricks🇺🇸 · Zhuoni Qian🇺🇸 · Ning Zhou🇨🇳

   We study the Higgs boson $(h)$ decay to two light jets at the 14 TeV High-Luminosity-LHC (HL-LHC), where a light jet ($j$) represents any non-flavor tagged jet from the observational point of view. The decay mode $h\to gg$ is chosen as the benchmark since it is the dominant channel in the Standard Model (SM), but the bound obtained is also applicable to the light quarks $(j=u,d,s)$. We estimate the achievable bounds on the decay branching fractions through the associated production $Vh(V=W^{\pm },Z)$. Events of the Higgs boson decaying into heavy (tagged) or light (un-tagged) jets are correlatively analyzed. We find that with 3000 fb${}^{-1}$ data at the HL-LHC, we should expect approximately $1\sigma$ statistical significance on the SM $Vh(gg)$ signal in this channel. This corresponds to a reachable upper bound $\mathrm{BR}(h\to jj)\le 4{\mathrm{BR}}^{SM}(h\to gg)$ at $95\%$ confidence level. A consistency fit also leads to an upper bound $\mathrm{BR}(h\to cc)<15{\mathrm{BR}}^{SM}(h\to cc)$ at $95\%$ confidence level. The estimated bound may be further strengthened by adopting multiple variable analyses, or adding other production channels.

   hep-phhep-exPRD(2017)·30 citations
4. 04*

   Sphalerons in composite and non-standard Higgs models

   Michael Spannowsky🇬🇧 · Carlos Tamarit🇬🇧

   After the discovery of the Higgs boson and the rather precise measurement of all electroweak boson's masses the local structure of the electroweak symmetry breaking potential is already quite well established. However, despite being a key ingredient to a fundamental understanding of the underlying mechanism of electroweak symmetry breaking, the global structure of the electroweak potential remains entirely unknown. The existence of sphalerons, unstable solutions of the classical action of motion that are interpolating between topologically distinct vacua, is a direct consequence of the Standard Model's $\mathrm{SU}(2{)}_L$ gauge group. Nevertheless, the sphaleron energy depends on the shape of the Higgs potential away from the minimum and can therefore be a litmus test for its global structure. Focusing on two scenarios, the minimal composite Higgs model $\mathrm{SO}(5)/\mathrm{SO}(4)$ or an elementary Higgs with a deformed electroweak potential, we calculate the change of the sphaleron energy compared to the Standard Model prediction. We find that the sphaleron energy would have to be measured to $\mathcal{O}(10)\%$ accuracy to exclude sizeable global deviations from the Standard Model Higgs potential. We further find that because of the periodicity of the scalar potential in composite Higgs models a second sphaleron branch with larger energy arises.

   hep-phhep-thPRD(2017)·36 citations
5. 05*

   Accessing transverse nucleon and gluon distributions in heavy nuclei using coherent vector meson photoproduction at high energies in ion ultraperipheral collisions

   V. Guzey (St. Petersburg, INP)🇷🇺 · M. Strikman (Penn State U.)🇺🇸 · M. Zhalov (St. Petersburg, INP)🇷🇺

   By using the theoretical approaches describing well the available data on $t$-integrated coherent photoproduction of light and heavy vector mesons in Pb-Pb ultraperipheral collisions (UPCs) at the Large Hadron Collider (LHC) in Run 1, we calculate the momentum transfer distributions for this process for $\rho$ and $J/\psi$ vector mesons in the kinematics of Run 2 at the LHC. We demonstrate that nuclear shadowing not only suppresses the absolute value of the cross sections, but also shifts the momentum transfer distributions toward smaller values of the momentum transfer $|t|$. This result can be interpreted as a broadening in the impact parameter space of the effective nucleon density in nuclei by 14\% in the case of $\rho$ and the nuclear gluon distribution by $5-11$\% in the case of $J/\psi$.

   hep-phhep-exnucl-exPRC(2017)·59 citations
6. 06*

   Vector-Like Quarks and Leptons, SU(5) $\otimes$ SU(5) Grand Unification, and Proton Decay

   Chang-Hun Lee🇺🇸 · Rabindra N. Mohapatra🇺🇸

   SU(5) $\otimes$ SU(5) provides a minimal grand unification scheme for fermions and gauge forces if there are vector-like quarks and leptons in nature. We explore the gauge coupling unification in a non-supersymmetric model of this type, and study its implications for proton decay. The properties of vector-like quarks and intermediate scales that emerge from coupling unification play a central role in suppressing proton decay. We find that in this model, the familiar decay mode $p\to e^{+}{\pi }^0$ may have a partial lifetime within the reach of currently planned experiments.

   hep-phJHEP(2017)·19 citations
7. 07*

   Spin-1 diquark contributing to the formation of tetraquarks in light mesons

   Hungchong Kim🇰🇷 · Myung-Ki Cheoun🇰🇷 · K. S. Kim🇰🇷

   We apply a mixing framework to the light meson systems and examine tetraquark possibility in the scalar channel. In the diquark-antidiquark model, a scalar diquark is a compact object when its color and flavor structures are in (${\bar{3}}_c$, ${\bar{3}}_f$). Assuming that all the quarks are in an $S$-wave, the spin-0 tetraquark formed out of this scalar diquark has only one spin configuration, $|J,J_{12},J_{34}⟩=|000⟩$, where $J$ is the spin of the tetraquark, $J_{12}$ the diquark spin, $J_{34}$ the antidiquark spin. In this construction of the scalar tetraquark, we notice that another compact diquark with spin-1 in ($6_c$, ${\bar{3}}_f$) can be used although it is less compact than the scalar diquark. The spin-0 tetraquark constructed from this vector diquark leads to the spin configuration $|J,J_{12},J_{34}⟩=|011⟩$. The two configurations, $|000⟩$ and $|011⟩$, are found to mix strongly through the color-spin interaction. The physical states can be identified with certain mixtures of the two configurations which diagonalize the hyperfine masses of the color-spin interaction. Matching these states to two scalar resonances $a_0(980),a_0(1450)$ or to $K_0^{\ast }(800),K_0^{\ast }(1430)$ depending on the isospin channel, we find that their mass splittings are qualitatively consistent with the hyperfine mass splittings which can support their tetraquark structure. To test our mixing scheme further, we also construct the tetraquarks for $J=1,J=2$ with the spin configurations, $|111⟩$ and $|211⟩$, and discuss possible candidates in the physical spectrum.

   hep-phnucl-thEPJC(2017)·17 citations
8. 08*

   Self-interacting scalar fields at high-temperature

   A. Deur🇺🇸

   We study two self-interacting scalar field theories in their high-temperature limit using path integrals on a lattice. We first discuss the formalism and recover known potentials to validate the method. We then discuss how these theories can model, in the high-temperature limit, the strong interaction and General Relativity. For the strong interaction, the model recovers the known phenomenology of the nearly static regime of heavy quarkonia. The model also exposes a possible origin for the emergence of the confinement scale from the approximately conformal Lagrangian. Aside from such possible insights, the main purpose of addressing the strong interaction here --given that more sophisticated approaches already exist-- is mostly to further verify the pertinence of the model in the more complex case of General Relativity for which non-perturbative methods are not as developed. The results have important implications on the nature of Dark Matter. In particular, non-perturbative effects naturally provide flat rotation curves for disk galaxies, without need for non-baryonic matter, and explain as well other observations involving Dark Matter such as cluster dynamics or the dark mass of elliptical galaxies.

   hep-phastro-ph.GAgr-qcEPJC(2017)·20 citations
9. 09*

   Prompt atmospheric neutrino flux from the various QCD models

   Yu Seon Jeong🇰🇷 · Atri Bhattacharya🇧🇪 · Rikard Enberg🇸🇪 · C. S. Kim🇰🇷 · Mary Hall Reno🇺🇸 · Ina Sarcevic🇺🇸 · Anna Stasto🇺🇸

   We evaluate the prompt atmospheric neutrino flux using the different QCD models for heavy quark production including the $b$ quark contribution. We include the nuclear correction and find it reduces the fluxes by $10\%-50\%$ according to the models. Our heavy quark results are compared with experimental data from RHIC, LHC and LHCb.

   hep-phastro-ph.HEEPJ Web Conf.(2017)·3 citations
10. 10*

    Phenomenology of Standard Model in spontaneously broken mirror symmetry

    Igor T. Dyatlov🇷🇺

    Violated mirror symmetry (MS) is capable of reproducing observed qualitative properties of weak mixing for quarks and leptons. In violated MS, lepton phenomenology, that is, small neutrino masses and mixing properties different from those of quarks, requires the Dirac nature of neutrinos and existence of processes that change the total lepton number. Such processes involve heavy mirror neutrinos, and therefore occur at very high energies. CP non-conservation would mean here that the parity conserving MS Lagrangian must be non-invariant to both time reversal T and (according to the CPT theorem) the charge conjugation C. All these properties create appropriate conditions for leptogenesis, a mechanism for generating baryon-lepton asymmetry of the Universe in violated MS models.

    hep-phPhys.Atom.Nucl.(2017)·3 citations
11. 11*

    Charm quark mass determined from a pair of sum rules

    Jens Erler🇲🇽 · Pere Masjuan🇩🇪 · Hubert Spiesberger🇩🇪

    In this paper, we present preliminary results of the determination of the charm quark mass ${\hat{m}}_c$ from QCD sum rules of moments of the vector current correlator calculated in perturbative QCD at $\mathcal{O}({\hat{\alpha }}_s^3)$. Self-consistency between two different sum rules allow to determine the continuum contribution to the moments without requiring experimental input, except for the charm resonances below the continuum threshold. The existing experimental data from the continuum region is used, then, to confront the theoretical determination and reassess the theoretic uncertainty.

    hep-phMod.Phys.Lett.A(2016)·2 citations
12. 12*

    New Physics in Astrophysical Neutrino Flavor (NuFact 2016)

    Jordi Salvado🇪🇸 · Carlos Argüelles🇺🇸 · Teppei Katori🇬🇧

    Astrophysical neutrinos are powerful tools to study fundamental properties of particle physics. We perform a general new physics study on ultra high energy neutrino flavor content by introducing effective operators. We find that at the current limits on these operators, new physics terms cause maximal effects on the flavor content, however, the flavor content at Earth is confined to a region related to the initial flavor content.

    hep-ph0 citations
13. 13*

    Testable Baryogenesis in Seesaw Models (NuFact 2016)

    J. Salvado🇪🇸 · P. Hernández🇪🇸 · M. Kekic🇪🇸 · J. López-Pavón🇮🇹 · J. Racker🇪🇸

    We revisit the production of baryon asymmetries in the minimal type I seesaw model with heavy Majorana singlets in the GeV range. We include "washout" effects from scattering processes with gauge bosons, higgs decays and inverse decays, besides the dominant top scatterings. We show that in the minimal model with two singlets, and for an inverted light neutrino ordering, future measurements from SHiP and neutrinoless double beta decay could in principle provide sufficient information to predict the matter-antimatter asymmetry in the universe.

    hep-ph0 citations
14. 14*

    Disfavouring Electroweak Baryogenesis and a hidden Higgs in a CP-violating Two-Higgs-Doublet Model

    Anders Haarr🇳🇴 · Anders Kvellestad🇸🇪 · Troels C. Petersen🇩🇰

    A strongly first-order electroweak phase transition is a necessary requirement for Electroweak Baryogenesis. We investigate the plausibility of obtaining a strong phase transition in a Two-Higgs-Doublet Model of type II with a minimal amount of $CP$ violation. By performing a Bayesian fit where we constrain the scalar sector with indirect and direct measurements, we find that current data disfavours a first-order phase transition in this model. This result is mainly driven by the interplay of three effects: Constraints from the LHC Higgs data on the magnitude of the quartic couplings, the requirement of a $H^{\pm }$ heavier than around 490 GeV to avoid large contributions to $BR(b\to s\gamma )$ and the fact that a first-order phase transition requires relatively light scalar states in addition to the 125 GeV Higgs. For similar reasons we find that a "hidden-Higgs" scenario, in which the 125 GeV state is identified with the next-to-lightest scalar, is disfavoured by current data independent of any requirement on the phase transition strength.

    hep-ph27 citations
15. 15*

    Chiral magnetic plasmons in anomalous relativistic matter

    E. V. Gorbar🇺🇦 · V. A. Miransky🇨🇦 · I. A. Shovkovy🇺🇸 · P. O. Sukhachov🇨🇦

    The chiral plasmon modes of relativistic matter in background magnetic and strain-induced pseudomagnetic fields are studied in detail using the consistent chiral kinetic theory. The results reveal a number of anomalous features of these chiral magnetic and pseudomagnetic plasmons that could be used to identify them in experiment. In a system with nonzero electric (chiral) chemical potential, the background magnetic (pseudomagnetic) fields not only modify the values of the plasmon frequencies in the long-wavelength limit, but also affect the qualitative dependence on the wave vector. Similar modifications can be also induced by the chiral shift parameter in Weyl materials. Interestingly, even in the absence of the chiral shift and external fields, the chiral chemical potential alone leads to a splitting of plasmon energies at linear order in the wave vector.

    ↳ cond-mat.mes-hallhep-phhep-thnucl-thPRB(2017)·36 citations
16. 16*

    New Results for Ultraperipheral Heavy Ion Collisions

    Antoni Szczurek🇵🇱 · Mariola Klusek-Gawenda🇵🇱 · Piotr Lebiedowicz🇵🇱 · Wolfgang Schäfer🇵🇱

    We discuss diphoton semi(exclusive) production in ultraperipheral $PbPb$ collisions at energy of $\sqrt{s_{NN}}=$ 5.5 TeV (LHC). The nuclear calculations are based on equivalent photon approximation in the impact parameter space. The cross sections for elementary $\gamma \gamma \to \gamma \gamma$ subprocess are calculated including three different mechanisms: box diagrams with leptons and quarks in the loops, a VDM-Regge contribution with virtual intermediate hadronic excitations of the photons and the two-gluon exchange contribution (formally three-loops). We got relatively high cross sections in $PbPb$ collisions. This opens a possibility to study the $\gamma \gamma \to \gamma \gamma$ (quasi)elastic scattering at the LHC. We find that the cross section for elastic $\gamma \gamma$ scattering could be measured in the lead-lead collisions for the diphoton invariant mass up to $W_{\gamma \gamma }\approx 15-20$ GeV. We identify region(s) of phase space where the two-gluon exchange contribution becomes important ingredient compared to box and nonperturbative VDM-Regge mechanisms. We discuss also first results concerning production of two $e^{+}{e}^{-}$ pairs in UPCs of heavy ions. We considered only double scattering mechanism.

    ↳ nucl-thhep-phAIP Conf.Proc.(2017)·2 citations
17. 17*

    The determination of ${\alpha }_s$ by the ALPHA collaboration

    Mattia Bruno🇺🇸 · Mattia Dalla Brida🇩🇪 · Patrick Fritzsch🇪🇸 · Tomasz Korzec🇩🇪 · Alberto Ramos🇨🇭 · Stefan Schaefer🇩🇪 · Hubert Simma🇩🇪 · Stefan Sint🇮🇪 · Rainer Sommer🇩🇪

    We review the ALPHA collaboration strategy for obtaining the QCD coupling at high scale. In the three-flavor effective theory it avoids the use of perturbation theory at $\alpha >0.2$ and at the same time has the physical scales small compared to the cutoff $1/a$ in all stages of the computation. The result \Lambda_\overline{MS}^{(3)}=332(14)~MeV is translated to \alpha_\overline{MS}(m_Z)=0.1179(10)(2) by use of (high order) perturbative relations between the effective theory couplings at the charm and beauty quark "thresholds". The error of this perturbative step is discussed and estimated as $0.0002$.

    ↳ hep-lathep-phNucl.Part.Phys.Proc.(2017)·4 citations
18. 18*

    In-Medium Pion Valence Distribution Amplitude

    K. Tsushima (Cruzeiro do Sul U.)🇧🇷 · J. P. B. C de Melo (Cruzeiro do Sul U.)🇧🇷

    After a brief review of the quark-based model for nuclear matter, and some pion properties in medium presented in our previous works, we report new results for the pion valence wave function as well as the valence distribution amplitude in medium, which are presented in our recent article. We find that both the in-medium pion valence distribution and the in-medium pion valence wave function, are substantially modified at normal nuclear matter density, due to the reduction in the pion decay constant.

    ↳ nucl-thhep-exhep-phnucl-exFew Body Syst.(2017)·3 citations
19. 19*

    Entropic destruction of a rotating heavy quarkonium

    Zi-qiang Zhang🇨🇳 · Chong Ma🇨🇳 · De-fu Hou🇨🇳 · Gang Chen🇨🇳

    Using the AdS/CFT duality, we study the destruction of a rotating heavy quarkonium due to the entropice force in $\mathcal{N}=4$ SYM theory and a confining YM theory. It is shown that in both theories increasing the angular velocity leads to decreasing the entropic force. This result implies that the rotating quarkonium dissociates harder than the static case.

    ↳ hep-thhep-ph11 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.