Thu·Apr 28, 2016Thursday·April 28, 2016

1. 01*

   Diphoton Signals from Colorless Hidden Quarkonia

   Sho Iwamoto🇮🇱 · Gabriel Lee🇮🇱 · Yael Shadmi🇮🇱 · Robert Ziegler🇫🇷

   We show that quarkonia-like states of a hidden SU(N) gauge group can account for the 750 GeV diphoton excess observed by ATLAS and CMS, even with constituents carrying standard model hypercharge only. The required hypercharge is modest, varying between about 1.3-1.6 for strong SU(N) coupling, to 2-3 for weak SU(N) coupling, for N=3, 4. This scenario predicts a variety of diphoton and multi-photon resonances, as well as photons from continuum pair production, and possibly exotic decays into standard model fermions, with no multi-jet resonances.

   hep-phPRD(2016)·15 citations
2. 02*

   Scotogenic model for co-bimaximal mixing

   P.M. Ferreira🇵🇹 · W. Grimus🇦🇹 · D. Jurciukonis🇱🇹 · L. Lavoura🇵🇹

   We present a scotogenic model, i.e. a one-loop neutrino mass model with dark right-handed neutrino gauge singlets and one inert dark scalar gauge doublet $\eta$, which has symmetries that lead to co-bimaximal mixing, i.e. to an atmospheric mixing angle ${\theta }_{23}=45^{\circ }$ and to a $CP$-violating phase $\delta =\pm \pi /2$, while the mixing angle ${\theta }_{13}$ remains arbitrary. The symmetries consist of softly broken lepton numbers $L_{\alpha }$ ($\alpha =e,\mu ,\tau$), a non-standard $CP$ symmetry, and three $Z_2$ symmetries. We indicate two possibilities for extending the model to the quark sector. Since the model has, besides $\eta$, three scalar gauge doublets, we perform a thorough discussion of its scalar sector. We demonstrate that it can accommodate a Standard Model-like scalar with mass $125\mathrm{GeV}$, with all the other charged and neutral scalars having much higher masses.

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

   Models of 750 GeV quarkonium and the LHC excesses

   Koichi Hamaguchi🇯🇵 · Seng Pei Liew🇯🇵

   We investigate models involving a vector-like quark X, which forms a 750 GeV bound state and reproduces the observed diphoton signals at the LHC, in connection with other excesses in the LHC data. An exotic hypercharge of -4/3 is required to fit the signal cross section, which indicates that there is additional particle(s) that mediates the decay of X in the full theory. We find that, introducing an SU(2) doublet vector-like quark of mass around 600 GeV in our UV-complete framework can accommodate not only the diphoton but also the on-Z excess (and potentially a slight excess in the monojet events). Our models also include a dark matter candidate. The most useful way to probe the models at the LHC is via monojet searches. The relic dark matter density is largely determined by coannihilation effects, and indirect detection of dark matter annihilation signals is the alternative and complementary probe of our models.

   hep-phastro-ph.COhep-exPRD(2016)·12 citations
4. 04*

   Color-octet Companions of a 750 GeV Heavy Pion

   Yang Bai🇺🇸 · Vernon Barger🇺🇸 · Joshua Berger🇺🇸

   Color octet bosons are a universal prediction of models in which the 750 GeV diphoton resonance corresponds to a pion of a QCD-like composite sector. We show that the existing searches for dijet and photon plus jet resonances at the LHC constrain single productions of color octet states and can be translated into stringent limits on the 750 GeV diphoton rate. For a minimal 5 + 5bar model, the 750 GeV diphoton signal cross section at the 13 TeV LHC is constrained to be below around 5 fb. Future LHC searches for the photon plus jet resonances can establish evidence of a new color-octet state with 20/fb and validate a pion-like explanation for the 750 GeV resonance.

   hep-phhep-exPRD(2016)·18 citations
5. 05*

   An SU(6) GUT Origin of the TeV-Scale Vector-like Particles Associated with the 750 GeV Diphoton Resonance

   Bhaskar Dutta🇺🇸 · Yu Gao🇺🇸 · Tathagata Ghosh🇺🇸 · Ilia Gogoladze🇺🇸 · Tianjun Li🇨🇳 · Joel W. Walker🇺🇸

   We consider the $SU(6)$ GUT model as an explanation for the diphoton final state excess, where the masses of all associated particles are linked with a new symmetry breaking scale. In this model, the diphoton final states arise due to loops involving three pairs of new vector-like particles having the same quantum numbers as down-type quarks and lepton doublets. These new vector-like fermions are embedded alongside the SM fermions into minimal anomaly-free representations of the $SU(6)$ gauge symmetry. The $SU(6)$ symmetry is broken to the Standard Model times $U(1{)}_X$ at the GUT scale, and masses for the vector-like fermions arise at the TeV scale only after the residual $U(1{)}_X$ symmetry is broken. The vector-like fermions do not acquire masses via breaking of the SM symmetry at the EW scale. The field which is responsible for the newly observed resonance belongs to the ${\bar{6}}_H$ representation. The dark matter arises from the SM singlet fermion residing in $\bar{6}$ and is of Majorana type. We explicitly demonstrate gauge coupling unification in this model, and also discuss the origin of neutrino masses. In addition to the diphoton final states, we make distinctive predictions for other final states which are likewise accessible to the ongoing LHC experimental effort.

   hep-phPRD(2016)·13 citations
6. 06*

   Black holes and gravitational waves in models of minicharged dark matter

   Vitor Cardoso🇵🇹 · Caio F. B. Macedo🇵🇹 · Paolo Pani🇮🇹 · Valeria Ferrari🇮🇹

   In viable models of minicharged dark matter, astrophysical black holes might be charged under a hidden $U(1)$ symmetry and are formally described by the same Kerr-Newman solution of Einstein-Maxwell theory. These objects are unique probes of minicharged dark matter and dark photons. We show that the recent gravitational-wave detection of a binary black-hole coalescence by aLIGO provides various observational bounds on the black hole's charge, regardless of its nature. The pre-merger inspiral phase can be used to constrain the dipolar emission of (ordinary and dark) photons, whereas the detection of the quasinormal modes set an upper limit on the final black hole's charge. By using a toy model of a point charge plunging into a Reissner-Nordstrom black hole, we also show that in dynamical processes the (hidden) electromagnetic quasinormal modes of the final object are excited to considerable amplitude in the gravitational-wave spectrum only when the black hole is nearly extremal. The coalescence produces a burst of low-frequency dark photons which might provide a possible electromagnetic counterpart to black-hole mergers in these scenarios.

   hep-phastro-ph.HEgr-qchep-thJCAP(2016)·147 citations
7. 07*

   Generalized Dirac duality and CP violation in a two photon theory

   P. Arias🇨🇱 · A. K. Das🇺🇸 · J. Gamboa🇨🇱 · F. Mendez🇨🇱

   A kinetic mixing term, which generalizes the duality symmetry of Dirac, is studied in a theory with two photons (visible and hidden). This theory can be either CP conserving or CP violating depending on the transformation of fields in the hidden sector. However if CP is violated, it necessarily occurs in the hidden sector. This opens up an interesting possibility of new sources of CP violation.

   hep-phhep-thMod.Phys.Lett.A(2017)·0 citations
8. 08*

   Unpolarized Transverse Momentum Dependent Parton Distribution and Fragmentation Functions at next-to-next-to-leading order

   Miguel G. Echevarria🇪🇸 · Ignazio Scimemi🇪🇸 · Alexey Vladimirov🇩🇪

   The transverse momentum dependent parton distribution/fragmentation functions (TMDs) are essential in the factorization of a number of processes like Drell-Yan scattering, vector boson production, semi-inclusive deep inelastic scattering, etc. We provide a comprehensive study of unpolarized TMDs at next-to-next-to-leading order, which includes an explicit calculation of these TMDs and an extraction of their matching coefficients onto their integrated analogues, for all flavor combinations. The obtained matching coefficients are important for any kind of phenomenology involving TMDs. In the present study each individual TMD is calculated without any reference to a specific process. We recover the known results for parton distribution functions and provide new results for the fragmentation functions. The results for the gluon transverse momentum dependent fragmentation functions are presented for the first time at one and two loops. We also discuss the structure of singularities of TMD operators and TMD matrix elements, crossing relations between TMD parton distribution functions and TMD fragmentation functions, and renormalization group equations. In addition, we consider the behavior of the matching coefficients at threshold and make a conjecture on their structure to all orders in perturbation theory.

   hep-phhep-thJHEP(2016)·237 citations
9. 09*

   Systematic U(1)_{B-L} Extensions of Loop-Induced Neutrino Mass Models with Dark Matter

   Shu-Yu Ho🇺🇸 · Takashi Toma🇫🇷 · Koji Tsumura🇯🇵

   We study the gauged U(1)_{B-L} extensions of the models for neutrino masses and dark matter. In this class of models, tiny neutrino masses are radiatively induced through the loop diagrams, while the origin of the dark matter stability is guaranteed by the remnant of the gauge symmetry. Depending on how the lepton number is violated in the neutrino mass diagrams, these models are systematically classified. We present a complete list for the one-loop Z_2 and the two-loop Z_3 neutrino mass models as examples of the classification. These underlying gauge symmetries and its breaking patterns can be probed at future high energy colliders by looking at the width of the new gauge boson.

   hep-phPRD(2016)·36 citations
10. 10*

    Hierarchical majorana neutrinos from democratic mass matrices

    Masaki J. S. Yang🇯🇵

    In this paper, we obtain the light neutrino masses and mixings consistent with the experiments, in the democratic texture approach. The essential ansatz is that ${\nu }_{Ri}$ are assumed to transform as "right-handed fields" $2_{\mathbf{R}}+1_{\mathbf{R}}$ under the $S_{3L}\times S_{3R}$ symmetry. The symmetry breaking terms are assumed to be diagonal and hierarchical. This setup only allows the normal hierarchy of the neutrino mass, and excludes both of inverted hierarchical and degenerated neutrinos. Although the neutrino sector has nine free parameters, several predictions are obtained at the leading order. When we neglect the smallest parameters ${\zeta }_{\nu }$ and ${\zeta }_R$, all components of the mixing matrix $U_{\mathrm{PMNS}}$ are expressed by the masses of light neutrinos and charged leptons. From the consistency between predicted and observed $U_{\mathrm{PMNS}}$, we obtain the lightest neutrino masses $m_1$ = (1.1 $\to$ 1.4) meV, and the effective mass for the double beta decay $\text{vev}{m}_{ee}\simeq$ 4.5 meV.

    hep-phPLB(2016)·9 citations
11. 11*

    Electroweak radiative corrections to triple photon production at the ILC

    Yu Zhang🇨🇳 · Wei-Hua Li🇨🇳 · Peng-Fei Duan🇨🇳 · Mao Song🇨🇳 · Gang Li🇨🇳

    In this paper, we present the precision predictions for three photon production in the standard model (SM) at the ILC including the full next-to-leading (NLO) electroweak (EW) corrections, high order initial state radiation (h.o.ISR) contributions and beamstrahlung effects. We present the LO and the NLO EW+h.o.ISR+beamstrahlung corrected total cross sections for various colliding energy when $\sqrt{s}\ge 200\mathrm{GeV}$ and the kinematic distributions of final photons with $\sqrt{s}=500\mathrm{GeV}$ at ILC, and find that the NLO EW corrections, the h.o.ISR contributions and the beamstrahlung effects are important in exploring the process $e^{+}{e}^{-}\to \gamma \gamma \gamma$.

    hep-phPLB(2016)·3 citations
12. 12*

    From the 750 GeV Diphoton Resonance to Multilepton Excesses

    Kyu Jung Bae🇯🇵 · Chuan-Ren Chen🇹🇼 · Koichi Hamaguchi🇯🇵 · Ian Low🇺🇸

    Weakly-coupled models for the 750 GeV diphoton resonance often invoke new particles carrying both color and/or electric charges to mediate loop-induced couplings of the resonance to two gluons and two photons. The new colored particles may not be stable and could decay into final states containing standard model particles. We consider an electroweak doublet of vector-like quarks (VLQs) carrying electric charges of 5/3 and 2/3, respectively, which mediate the loop-induced couplings of the 750 GeV resonance. If the VLQ has a mass at around 1 TeV, it naturally gives rise to the observed diphoton signal strength while all couplings remain perturbative up to a high scale. At the same time, if the charge-5/3 VLQ decays into final states containing top quark and W boson, it would contribute to the multilepton excesses observed in both Run 1 and Run 2 data. It is also possible to incorporate a dark matter candidate in the decay final states to explain the observed relic density.

    hep-phhep-exPRD(2016)·10 citations
13. 13*

    S-Channel Dark Matter Simplified Models and Unitarity

    Christoph Englert🇬🇧 · Matthew McCullough🇨🇭 · Michael Spannowsky🇬🇧

    The ultraviolet structure of $s$-channel mediator dark matter simplified models at hadron colliders is considered. In terms of commonly studied $s$-channel mediator simplified models it is argued that at arbitrarily high energies the perturbative description of dark matter production in high energy scattering at hadron colliders will break down in a number of cases. This is analogous to the well documented breakdown of an EFT description of dark matter collider production. With this in mind, to diagnose whether or not the use of simplified models at the LHC is valid, perturbative unitarity of the scattering amplitude in the processes relevant to LHC dark matter searches is studied. The results are as one would expect: at the LHC and future proton colliders the simplified model descriptions of dark matter production are in general valid. As a result of the general discussion, a simple new class of previously unconsidered `Fermiophobic Scalar' simplified models is proposed, in which a scalar mediator couples to electroweak vector bosons. The Fermiophobic simplified model is well motivated and exhibits interesting collider and direct detection phenomenology.

    hep-phPhys.Dark Univ.(2016)·90 citations
14. 14*

    Recent Pythia 8 developments: Hard diffraction, Colour reconnection and $\gamma \gamma$ collisions

    Ilkka Helenius🇸🇪 · Jesper R. Christiansen🇸🇪 · Christine O. Rasmussen🇸🇪

    An overview of recent developments in \pythia~8 is given. First the new hard diffraction model, which is implemented as a part of the multiparton interactions (MPI) framework, is discussed. Then the new colour reconnection model, which includes beyond leading colour effects that can become important when MPI are present, is briefly reviewed. As a last topic an introduction is given to our implementation of photon-photon collisions. In particular photon PDFs, required modifications for the initial state radiation algorithm and beam remnant handling with photon beams is discussed.

    hep-ph1 citation
15. 15*

    Improved Statistical Determination of Absolute Neutrino Masses via Radiative Emission of Neutrino Pairs from Atoms

    Jue Zhang🇨🇳 · Shun Zhou🇨🇳

    The atomic transition from an excited state $|\mathrm{e}⟩$ to the ground state $|\mathrm{g}⟩$ by emitting a neutrino pair and a photon, i.e., $|\mathrm{e}⟩\to |\mathrm{g}⟩+|\gamma ⟩+|{\nu }_i^{}⟩+|{\bar{\nu }}_j^{}⟩$ with $i,j=1,2,3$, has been proposed by Yoshimura and his collaborators as an alternative way to determine the absolute scale $m_0^{}$ of neutrino masses. More recently, a statistical analysis of the fine structure of the photon spectrum from this atomic process has been performed [N. Song {\it et al.}, Phys.\ Rev.\ D {\bf 93}, 013020 (2016)] to quantitatively examine the experimental requirements for a realistic determination of absolute neutrino masses. In this paper, we show how to improve the statistical analysis and demonstrate that the previously required detection time can be reduced by one order of magnitude for the case of a $3\sigma$ determination of $m_0^{}\sim 0.01\text{eV}$ with an accuracy better than $10\%$. Such an improvement is very encouraging for further investigations on measuring absolute neutrino masses through atomic processes.

    hep-phPRD(2016)·12 citations
16. 16*

    High-Energy Resummation in Di-hadron Production at the LHC

    Francesco G. Celiberto🇮🇹 · Dmitry Yu. Ivanov🇷🇺 · Beatrice Murdaca🇮🇹 · Alessandro Papa🇮🇹

    We propose to study at the Large Hadron Collider (LHC) the inclusive production of a pair of hadrons (a "di-hadron" system) in a kinematics where two detected hadrons with high transverse momenta are separated by a large interval of rapidity. This process has much in common with the widely discussed Mueller-Navelet jet production and can also be used to access the dynamics of hard proton-parton interactions in the Regge limit. For both processes large contributions enhanced by logarithms of energy can be resummed in perturbation theory within the Balitsky-Fadin-Kuraev-Lipatov (BFKL) formalism with next-to-leading logarithmic accuracy (NLA). The experimental study of di-hadron production would provide with an additional clear channel to test the BFKL dynamics. We present here the first theoretical predictions for cross sections and azimuthal angle correlations of the di-hadrons produced with LHC kinematics.

    hep-phPRD(2016)·93 citations
17. 17*

    The discrete family symmetry as a possible solution to the flavour problem

    Bartosz Dziewit🇵🇱 · Jacek Holeczek🇵🇱 · Monika Richter🇵🇱 · Sebastian Zając🇵🇱 · Marek Zrałek🇵🇱

    In order to explain the fermions masses and mixing parameters appearing in the lepton sector of the Standard Model, one proposes the extension of its symmetry. A discrete, non-abelian subgroup of $U(3)$ is added to the gauge group $SU(3{)}_C\times SU(2{)}_L\times U(1{)}_Y$ . Apart from that, one assumes the existence of one extra Higgs doublet. This article focuses mainly on the mathematical theorems and computational techniques which brought us to the results.

    hep-phhep-thPhys.Atom.Nucl.(2017)·1 citation
18. 18*

    The QCD Running Coupling

    A. Deur🇺🇸 · S. J. Brodsky🇺🇸 · G. F. de Teramond🇨🇷

    We review the present knowledge for ${\alpha }_s$, the fundamental coupling underlying the interactions of quarks and gluons in QCD. The dependence of ${\alpha }_s(Q^2)$ on momentum transfer $Q$ encodes the underlying dynamics of hadron physics -from color confinement in the infrared domain to asymptotic freedom at short distances. We review constraints on ${\alpha }_s(Q^2)$ at high $Q^2$, as predicted by perturbative QCD, and its analytic behavior at small $Q^2$, based on models of nonperturbative dynamics. In the introductory part of this review, we explain the phenomenological meaning of ${\alpha }_s$, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss the behavior of ${\alpha }_s(Q^2)$ in the high $Q^2$ domain of QCD. We review how ${\alpha }_s$ is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as Commensurate Scale Relations which connect the various definitions of ${\alpha }_s$ without renormalization-scale ambiguity. We also report recent measurements and theoretical analyses which have led to precise QCD predictions at high energy. In the last part of the review, we discuss the challenge of understanding the analytic behavior ${\alpha }_s(Q^2)$ in the infrared domain. We also review important methods for computing ${\alpha }_s$, including lattice QCD, the Schwinger-Dyson equations, the Gribov-Zwanziger analysis and light-front holographic QCD. After describing these approaches and enumerating their conflicting predictions, we discuss the origin of these discrepancies and how to remedy them. Our aim is not only to review the advances in this difficult area, but also to suggest what could be an optimal definition of ${\alpha }_s$ in order to bring better unity to the subject.

    hep-phNucl.Phys.(2016)·568 citations
19. 19*

    Updated scalar sector constraints in Higgs triplet model

    Dipankar Das🇪🇸 · Arcadi Santamaria🇪🇸

    We show that in the Higgs triplet model, after the Higgs discovery, the mixing angle in the CP-even sector can be strongly constrained from unitarity. We also discuss how large quantum effects in $h\to \gamma \gamma$ may arise in a SM-like scenario and a certain part of the parameter space can be ruled out from the diphoton signal strength. Using $T$-parameter and diphoton signal strength measurements, we update the bounds on the nonstandard scalar masses.

    hep-phPRD(2016)·56 citations
20. 20*

    Bounding quantum gravity inspired decoherence using atom interferometry

    Jiří Minář🇬🇧 · Pavel Sekatski🇦🇹 · Nicolas Sangouard🇨🇭

    Hypothetical models have been proposed in which explicit collapse mechanisms prevent the superposition principle to hold at large scales. In particular, the model introduced by Ellis and co-workers [Phys. Lett. B $221$, 113 (1989)] suggests that quantum gravity might be responsible for the collapse of the wavefunction of massive objects in spatial superpositions. We here consider a recent experiment reporting on interferometry with atoms delocalized over half a meter for timescale of a second [Nature $528$, 530 (2015)] and show that the corresponding data strongly bound quantum gravity induced decoherence and rule it out in the parameter regime considered originally.

    ↳ quant-phhep-phPRA(2016)·13 citations
21. 21*

    An introduction to cosmology

    Kerstin E. Kunze🇪🇸

    Cosmology is becoming an important tool to test particle physics models. We provide an overview of the standard model of cosmology with an emphasis on the observations relevant for testing fundamental physics.

    ↳ astro-ph.COhep-phhep-thCERN-2016-005, pp. 177-212·1 citation
22. 22*

    Loop Corrections to Standard Model Fields in Inflation

    Xingang Chen🇺🇸 · Yi Wang🇨🇳 · Zhong-Zhi Xianyu🇺🇸

    We calculate 1-loop corrections to the Schwinger-Keldysh propagators of Standard-Model-like fields of spin-0, 1/2, and 1, with all renormalizable interactions during inflation. We pay special attention to the late-time divergences of loop corrections, and show that the divergences can be resummed into finite results in the late-time limit using dynamical renormalization group method. This is our first step toward studying both the standard model and new physics in the primordial universe.

    ↳ hep-thastro-ph.COhep-phJHEP(2016)·144 citations
23. 23*

    Search for passing-through-walls neutrons constrains hidden braneworlds

    Michael Sarrazin🇧🇪 · Guillaume Pignol🇫🇷 · Jacob Lamblin🇫🇷 · Jonhathan Pinon🇫🇷 · Olivier Meplan🇫🇷 · Guy Terwagne🇧🇪 · Paul-Louis Debarsy🇧🇪 · Fabrice Petit🇧🇪 · Valery V. Nesvizhevsky🇫🇷

    In many theoretical frameworks our visible world is a $3$-brane, embedded in a multidimensional bulk, possibly coexisting with hidden braneworlds. Some works have also shown that matter swapping between braneworlds can occur. Here we report the results of an experiment - at the Institut Laue-Langevin (Grenoble, France) - designed to detect thermal neutron swapping to and from another braneworld, thus constraining the probability $p^2$ of such an event. The limit, $p<4.6\times 10^{-10}$ at $95\%$ C.L., is $4$ orders of magnitude better than the previous bound based on the disappearance of stored ultracold neutrons. In the simplest braneworld scenario, for two parallel Planck-scale branes separated by a distance $d$, we conclude that $d>87$ in Planck length units.

    ↳ hep-exhep-phnucl-exPLB(2016)·15 citations
24. 24*

    Gravitational Waves in Bouncing Cosmologies from Gauge Field Production

    Ido Ben-Dayan🇮🇱

    We calculate the gravitational waves (GW) spectrum produced in various Early Universe scenarios from gauge field sources, thus generalizing earlier inflationary calculations to bouncing cosmologies. We consider generic couplings between the gauge fields and the scalar field dominating the energy density of the Universe. We analyze the requirements needed to avoid a backreaction that will spoil the background evolution. When the scalar is coupled only to $F\tilde{F}$ term, the sourced GW spectrum is exponentially enhanced and parametrically the square of the vacuum fluctuations spectrum, ${\mathcal{P}}_T^s\sim ({\mathcal{P}}_T^v{)}^2$, giving an even bluer spectrum than the standard vacuum one. When the scalar field is also coupled to $F^2$ term, the amplitude is still exponentially enhanced, but the spectrum can be arbitrarily close to scale invariant (still slightly blue), $n_T\gtrsim 0$, that is distinguishable form the slightly red inflationary one. Hence, we have a proof of concept of observable GW on CMB scales in a bouncing cosmology.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2016)·39 citations
25. 25*

    Effects of electrically charged dark matter on cosmic microwave background anisotropies

    Ayuki Kamada🇺🇸 · Kazunori Kohri🇯🇵 · Tomo Takahashi🇯🇵 · Naoki Yoshida🇯🇵

    We examine the possibility that dark matter consists of charged massive particles (CHAMPs) in view of the cosmic microwave background (CMB) anisotropies. The evolution of cosmological perturbations of CHAMP with other components is followed in a self-consistent manner, without assuming that CHAMP and baryons are tightly coupled. We incorporate for the first time the "kinetic re-coupling" of the Coulomb scattering, which is characteristic of heavy CHAMPs. By a direct comparison of the predicted CMB temperature/polarization auto-correlations in CHAMP models and the observed spectra in the Planck mission, we show that CHAMPs leave sizable effects on CMB spectra if they are lighter than $10^{11}\mathrm{GeV}$. Our result can be applicable to any CHAMP as long as its lifetime is much longer than the cosmic time at the recombination ($\sim 4\times 10^5\mathrm{yr}$). An application to millicharged particles is also discussed.

    ↳ astro-ph.COhep-phPRD(2017)·28 citations
26. 26*

    Delta(1232) contribution to real photon radiative corrections for elastic electron-proton scattering

    R. E. Gerasimov🇷🇺 · V. S. Fadin🇷🇺

    Here we consider a contribution of Delta(1232) resonance to real photon radiative corrections for elastic $ep$-scattering. The effect is found to be small for past experiments to study unpolarized cross section as well as for the recent VEPP-3 experiment to investigate two-photon exchange effects by precision measurement of $e^{\pm }p$-scattering cross sections ratio.

    ↳ nucl-thhep-phJ.Phys.G(2016)·15 citations
27. 27*

    Field theoretical model of multi-layered Josephson junction and dynamics of Josephson vortices

    Toshiaki Fujimori🇯🇵 · Hideaki Iida🇯🇵 · Muneto Nitta🇯🇵

    Multi-layered Josephson junctions are modeled in the context of a field theory, and dynamics of Josephson vortices trapped inside insulators are studied. Starting from a theory consisting of complex and real scalar fields coupled to a U(1) gauge field which admit parallel $N-1$ domain-wall solutions, Josephson couplings are introduced weakly between the complex scalar fields. The $N-1$ domain walls behave as insulators separating $N$ superconductors, where one of the complex scalar fields has a gap. We construct the effective Lagrangian on the domain walls, which reduces to a coupled sine-Gordon model for well-separated walls We then construct sine-Gordon solitons emerging in an effective theory in which we identify Josephson vortices carrying singly quantized magnetic fluxes. When two neighboring superconductors tend to have the same phase, the ground state does not change with the positions of domain walls. On the other hand, when two neighboring superconductors tend to have $\pi$-phase differences, the ground state has a phase transition depending on the positions of domain walls; when the two walls are close to each other, frustration occurs because of the coupling between the two superconductors besides the thin superconductor. Focusing on the case of three superconductors separated by two insulators, we find for the former case that the interaction between two Josephson vortices on different insulators changes its nature, i.e., attractive or repulsive, depending on the positions of the domain walls. In the latter case, there emerges fractional Josephson vortices when two degenerate ground states appear due to spontaneous charge-symmetry breaking, and the number of the Josephson vortices varies with the position of the domain walls. Our predictions should be verified in multilayered Josephson junctions.

    ↳ cond-mat.supr-conhep-phhep-thPRB(2016)·10 citations
28. 28*

    Top physics at high-energy lepton colliders

    M. Vos🇪🇸 · G. Abbas🇪🇸 · M. Beneke🇩🇪 · S. Bilokin🇫🇷 · M. Costa🇪🇸 · S. De Curtis🇮🇹 · K. Fujii🇯🇵 · J. Fuster🇪🇸 · I. Garcia Garcia🇪🇸 · P. Gomis🇪🇸 · A. Hoang🇦🇹 · A. Irles🇩🇪 and 16 other authors

    A summary is presented of the workshop "top physics at linear colliders" that was held at IFIC Valencia from the 30th of June to the 3rd July 2015. We present an up-to-date status report of studies into the potential for top quark physics of lepton colliders with an energy reach that exceeds the top quark pair production threshold, with a focus on the linear collider projects ILC and CLIC. This summary shows that such projects can offer very competitive determinations of top quark properties (mass, width) and its interactions with other Standard Model particles, in particular electroweak gauge bosons and the Higgs boson. In both areas the prospects exceed the LHC potential significantly - often by an order of magnitude.

    ↳ hep-exhep-ph65 citations
29. 29*

    Revisiting the Contributions of Supernova and Hypernova Remnants to the Diffuse High-Energy Backgrounds: Constraints on Very-High-Redshift Injections

    Di Xiao🇨🇳 · Peter Mészáros🇺🇸 · Kohta Murase🇺🇸 · Zi-gao Dai🇨🇳

    Star-forming and starburst galaxies are considered as one of the viable candidate sources of the high-energy cosmic neutrino background detected in IceCube. We revisit contributions of supernova remnants (SNRs) and hypernova remnants (HNRs) in such galaxies to the diffuse high-energy neutrino and gamma-ray backgrounds, in light of the latest Fermi data above 50GeV. We also take into account possible time dependent effects of the cosmic-ray (CR) acceleration during the SNR evolution. CRs accelerated by the SNR shocks can produce high-energy neutrinos up to $\sim 100$ TeV energies, but CRs from HNRs can extend the spectrum up to PeV energies. We show that, only if HNRs are dominant over SNRs, the diffuse neutrino background above 100 TeV can be explained without contradicting the gamma-ray data. However, the neutrino data around 30 TeV remain unexplained, which might suggest a different population of gamma-ray dark CR sources. Alternatively, we consider possible contributions of Pop-III HNRs up to $z\lesssim 10$, and show that they are not constrained by the gamma-ray data, and thus could contribute to the diffuse high-energy backgrounds if their explosion energy reaches ${\mathcal{E}}_{\mathrm{POP}-\mathrm{III}}\sim \mathrm{a}\mathrm{few}\times 10^{53}$erg. More conservatively, our results suggest that the explosion energy of POP-III HNRs is ${\mathcal{E}}_{\mathrm{POP}-\mathrm{III}}\lesssim 7\times {10}^{53}$erg.

    ↳ astro-ph.HEastro-ph.GAhep-phApJ(2016)·40 citations
30. 30*

    Quark-hadron phase structure, thermodynamics and magnetization of QCD matter

    Abdel Nasser Tawfik🇪🇬 · Abdel Magied Diab (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo)🇪🇬 · M. T. Hussein (Cairo U.)🇪🇬

    SU($3$) Polyakov linear-sigma model (PLSM) is systematically implemented to characterize the quark-hadron phase structure and to determine various thermodynamic quantities and magnetization of the QCD matter. In mean-field approximation, the dependence of the chiral order-parameter on finite magnetic field is also calculated. In a wide range of temperatures and magnetic field strengths, various thermodynamic quantities including trace anomaly, speed of sound squared, entropy density, specific heat are presented and some magnetic properties are described, as well. Wherever available these results are confronted to recent lattice QCD calculations. The temperature dependence of these quantities confirms our previous result that the transition temperature is reduced with the increase in the magnetic field strength, i.e. QCD matter is to be characterized by an inverse magnetic catalysis. Furthermore, the temperature dependence of the magnetization shows that the conclusion that the QCD matter has paramagnetic properties slightly below and far above the pseudo-critical temperature, is confirmed, as well. The excellent agreement with recent lattice calculations proves that our QCD-like approach (PLSM) seems to possess the correct degrees-of-freedom in both hadronic and partonic phases and describes well the dynamics deriving confined hadrons to deconfined quark-gluon plasma.

    ↳ hep-lathep-phhep-thJ.Phys.G(2018)·36 citations
31. 31*

    Radio Galaxies Dominate the High-Energy Diffuse Gamma-Ray Background

    Dan Hooper🇺🇸 · Tim Linden🇺🇸 · Alejandro Lopez🇺🇸

    It has been suggested that unresolved radio galaxies and radio quasars (sometimes referred to as misaligned active galactic nuclei) could be responsible for a significant fraction of the observed diffuse gamma-ray background. In this study, we use the latest data from the Fermi Gamma-Ray Space Telescope to characterize the gamma-ray emission from a sample of 51 radio galaxies. In addition to those sources that had previously been detected using Fermi data, we report here the first statistically significant detection of gamma-ray emission from the radio galaxies 3C 212, 3C 411, and B3 0309+411B. Combining this information with the radio fluxes, radio luminosity function, and redshift distribution of this source class, we find that radio galaxies dominate the diffuse gamma-ray background, generating $77.2_{-9.4}^{+25.4}\%$ of this emission at energies above $\sim$1 GeV. We discuss the implications of this result and point out that it provides support for scenarios in which IceCube's high-energy astrophysical neutrinos also originate from the same population of radio galaxies.

    ↳ astro-ph.HEastro-ph.COhep-phJCAP(2016)·52 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.