Mon·Oct 24, 2016Monday·October 24, 2016

1. 01*

   Heavy Exotic Molecules

   Yizhuang Liu🇺🇸 · Ismail Zahed🇺🇸

   We briefly review the formation of pion-mediated heavy-light exotic molecules with both charm and bottom, under the general strictures of chiral and heavy quark symmetries. The charm isosinglet exotic molecules with $J^{PC}=1^{++}$ binds, which we identify as the reported neutral $X(3872)$. The bottom isotriplet exotic with $J^{PC}=1^{+-}$ binds, and is identified as a mixed state of the reported charged exotics $Z_b^{+}(10610)$ and $Z_b^{+}(10650)$. The bound bottom isosinglet molecule with $J^{PC}=1^{++}$ is a possible neutral $X_b(10532)$ to be observed.

   hep-phhep-exnucl-thIJMPE(2017)·6 citations
2. 02*

   Evolving Planck Mass in Classically Scale-Invariant Theories

   K. Kannike🇪🇪 · M. Raidal🇪🇪 · C. Spethmann🇪🇪 · H. Veermäe🇪🇪

   We consider classically scale-invariant theories with non-minimally coupled scalar fields, where the Planck mass and the hierarchy of physical scales are dynamically generated. The classical theories possess a fixed point, where scale invariance is spontaneously broken. In these theories, however, the Planck mass becomes unstable in the presence of explicit sources of scale invariance breaking, such as non-relativistic matter and cosmological constant terms. We quantify the constraints on such classical models from Big Bang Nucleosynthesis that lead to an upper bound on the non-minimal coupling and require trans-Planckian field values. We show that quantum corrections to the scalar potential can stabilise the fixed point close to the minimum of the Coleman-Weinberg potential. The time-averaged motion of the evolving fixed point is strongly suppressed, thus the limits on the evolving gravitational constant from Big Bang Nucleosynthesis and other measurements do not presently constrain this class of theories. Field oscillations around the fixed point, if not damped, contribute to the dark matter density of the Universe.

   hep-phhep-thJHEP(2017)·60 citations
3. 03*

   Is the dark matter particle its own antiparticle?

   Farinaldo S. Queiroz🇩🇪 · Werner Rodejohann🇩🇪 · Carlos E. Yaguna🇩🇪

   We propose a test based on direct detection data that allows to determine if the dark matter particle is different from its antiparticle. The test requires the precise measurement of the dark matter spin-independent direct detection cross sections off $\mathrm{three}$ different nuclei, and consists of interpreting such signals in terms of self-conjugate (particle $=$ antiparticle) dark matter to see if such interpretation is consistent. If it is not, the dark matter must be different from its antiparticle. We illustrate this procedure for two sets of target nuclei, $\{\mathrm{Xe},\mathrm{Ar},\mathrm{Si}\}$ and $\{\mathrm{Xe},\mathrm{Ar},\mathrm{Ge}\}$, identifying the regions of the parameter space where it is particularly feasible. Our results indicate that future signals in direct detection experiments, if sufficiently accurate, might be used to establish that the dark matter particle is not its own antiparticle --a major step towards the determination of the fundamental nature of the dark matter.

   hep-phastro-ph.HEhep-exPRD(2017)·32 citations
4. 04*

   Exotic colored scalars at the LHC

   Kfir Blum🇮🇱 · Aielet Efrati🇮🇱 · Claudia Frugiuele🇮🇱 · Yosef Nir🇮🇱

   We study the phenomenology of exotic color-triplet scalar particles $X$ with charge $|Q|=2/3,4/3,5/3,7/3,8/3$ and $10/3$. If $X$ is a non-singlet of $SU(2{)}_W$ representation, mass splitting within the multiplet allows for cascade decays of the members into the lightest state. We study examples where the lightest state, in turn, decays into a three-body $W^{\pm }jj$ final state, and show that in such case the entire multiplet is compatible with existing direct collider searches and indirect precision tests down to $m_X\sim 250$~GeV. However, bound states $S$, made of $X{X}^{†}$ pairs at $m_S\approx 2m_X$, form under rather generic conditions and their decay to diphoton can be the first discovery channel of the model. Furthermore, for $SU(2{)}_W$-non-singlets, the mode $S\to W^{+}{W}^{-}$ may be observable and the width of $S\to \gamma \gamma$ and $S\to jj$ may appear large as a consequence of mass splittings within the $X$-multiplet. As an example we study in detail the case of an $SU(2{)}_W$ quartet, finding that $m_X\simeq 450$~GeV is allowed by all current searches.

   hep-phJHEP(2017)·10 citations
5. 05*

   A Call for New Physics : The Muon Anomalous Magnetic Moment and Lepton Flavor Violation

   Manfred Lindner🇩🇪 · Moritz Platscher🇩🇪 · Farinaldo S. Queiroz🇩🇪

   We review how the muon anomalous magnetic moment ($g-2$) and the quest for lepton flavor violation are intimately correlated. Indeed the decay $\mu \to e\gamma$ is induced by the same amplitude for different choices of in- and outgoing leptons. In this work, we try to address some intriguing questions such as: Which hierarchy in the charged lepton sector one should have in order to reconcile possible signals coming simultaneously from $g-2$ and lepton flavor violation? What can we learn if the $g-2$ anomaly is confirmed by the upcoming flagship experiments at FERMILAB and J-PARC, and no signal is seen in the decay $\mu \to e\gamma$ in the foreseeable future? On the other hand, if the $\mu \to e\gamma$ decay is seen in the upcoming years, do we need to necessarily observe a signal also in $g-2$?. In this attempt, we generally study the correlation between these observables in a detailed analysis of simplified models. We derive master integrals and fully analytical and exact expressions for both phenomena, and adress other flavor violating signals. We investigate under which conditions the observations can be made compatible and discuss their implications. Lastly, we discuss in this context several extensions of the SM, such as the Minimal Supersymmetric Standard Model, Left-Right symmetric model, $B-L$ model, scotogenic model, two Higgs doublet model, Zee-Babu model, 331 model, and $L_{\mu }-L_{\tau }$, dark photon, seesaw models type~I, II and III, and also address the interplay with $\mu \to eee$ decay and $\mu -e$ conversion.

   hep-phPhys.Rept.(2018)·561 citations
6. 06*

   A composite tale of two right-handed neutrinos

   Gabriela Barenboim🇪🇸 · Cristian Bosch🇪🇸

   In this work, we develop a model for Higgs-like composites based on two generations of right handed neutrinos which condense. We analyze the Spontaneous Symmetry Breaking of the theory with two explicit breakings, setting the different scales of the model and obtaining massive bosons as a result. Finally, we calculate the gravitational wave imprint left by the phase transition associated to the symmetry breaking of a generic potential dictated by the symmetries of the composites.

   hep-phPRD(2016)·3 citations
7. 07*

   Di-boson signatures as Standard Candles for Partial Compositeness

   Alexander Belyaev🇬🇧 · Giacomo Cacciapaglia🇫🇷 · Haiying Cai🇫🇷 · Gabriele Ferretti🇸🇪 · Thomas Flacke🇰🇷 · Alberto Parolini🇰🇷 · Hugo Serodio🇰🇷

   Composite Higgs Models are often constructed including fermionic top partners with a mass around the TeV scale, with the top partners playing the role of stabilizing the Higgs potential and enforcing partial compositeness for the top quark. A class of models of this kind can be formulated in terms of fermionic strongly coupled gauge theories. A common feature they all share is the presence of specific additional scalar resonances, namely two neutral singlets and a colored octet, described by a simple effective Lagrangian. We study the phenomenology of these scalars, both in a model independent and model dependent way, including the bounds from all the available searches in the relevant channels with di-boson and di-top final states. We develop a generic framework which can be used to constrain any model containing pseudo-scalar singlets or octets. Using it, we find that such signatures provide strong bounds on the compositeness scale complementary to the traditional EWPT and Higgs couplings deviations. In many cases a relatively light scalar can be on the verge of discovery as a first sign of new physics.

   hep-phJHEP(2017)·135 citations
8. 08*

   Production of exotic charmonium in $\gamma \gamma$ interactions at hadronic colliders

   B. D. Moreira🇧🇷 · C. A. Bertulani🇺🇸 · V. P. Goncalves🇧🇷 · F. S. Navarra🇧🇷

   In this paper we investigate the Exotic Charmonium (EC) production in $\gamma \gamma$ interactions present in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC) energies as well as for the proposed energies of the Future Circular Collider (FCC). Our results demonstrate that the experimental study of these processes is feasible and can be used to constrain the theoretical decay widths and shed some light on the configuration of the considered multiquark states.

   hep-phhep-exnucl-exnucl-thPRD(2016)·31 citations
9. 09*

   Photoproduction of Upsilon states in ultraperipheral collisions at the CERN Large Hadron Collider within the color dipole approach

   M.B. Gay Ducati🇧🇷 · F. Kopp🇧🇷 · M.V.T. Machado🇧🇷 · S. Martins🇧🇷

   The exclusive photoproduction of upsilon states ${\rm Y}(1S)$ and its radially excited states ${\rm Y}(2S,3S)$ is investigated in the context of ultra-peripheral collisions at the LHC energies. Predictions are presented for their production in proton-proton, proton-nucleus and nucleus-nucleus collision at the energies available at the LHC run 2. The rapidity and transverse momentum distributions are shown, and the robustness of the model is tested against the experimental results considering $\psi (1S,2S)$ and ${\rm Y}(1S)$ states. The theoretical framework considered in the analysis is the light-cone color dipole formalism, which includes consistently parton saturation effects and nuclear shadowing corrections.

   hep-phPRD(2016)·28 citations
10. 10*

    Electric dipole moments of charged leptons at one loop in the presence of massive neutrinos

    H. Novales-Sánchez🇲🇽 · M. Salinas🇲🇽 · J. J. Toscano🇲🇽 · O. Vázquez-Hernández🇲🇽

    Violation of $CP$ invariance is a quite relevant phenomenon that is found in the Standard Model (SM), though in small amounts. This has been an incentive to look for high-energy descriptions in which $CP$ violation is increased, thus enhancing effects that are suppressed in the SM, such as the electric dipole moments (EDMs) of elementary particles. In the present investigation, we point out that charged currents in which axial couplings are different from vector couplings are able to produce one-loop contributions to EDMs of charged leptons if neutrinos are massive and if these currents violate $CP$. We develop our discussion around charged currents involving heavy neutrinos and a $W^{\prime }$ gauge boson coupling to SM charged leptons. Using the most stringent bound on the electron EDM, provided by the ACME Collaboration, we determine that the upper bound on the difference between axial and vector currents lies within $\sim 10^{-10}$ and $\sim 10^{-7}$ for heavy-neutrino masses between $0.5\mathrm{TeV}$ and $6\mathrm{TeV}$ and if the $W^{\prime }$ mass is within $0.45\mathrm{TeV}-7\mathrm{TeV}$. This possibility is analyzed altogether with the anomalous magnetic moments of charged leptons, among which we estimate, for the $\tau$ lepton, an anomalous magnetic moment contribution between $\sim 10^{-8}$ and $\sim 10^{-10}$ for neutrino masses ranging from $0.5\mathrm{TeV}$ to $6\mathrm{TeV}$ and a $W^{\prime }$ mass between $0.45\mathrm{TeV}$ and $7\mathrm{TeV}$. The general charged currents are also used to calculate the branching ratio for $\mu \to e\gamma$, which gets suppressed if the set of masses of heavy neutrinos is quasidegenerate. In a scenario of nondegenerate neutrino masses, we find that regions of neutrino and $W^{\prime }$ masses in which the contributions to this flavor changing branching ratio are lower than the current upper bound exist. We show that such regions can be widened if the $W^{\prime }$ gauge boson mass is larger.

    hep-phPRD(2017)·12 citations
11. 11*

    Implications of CP-violating Top-Higgs Couplings at LHC and Higgs Factories

    Archil Kobakhidze🇦🇺 · Ning Liu🇨🇳 · Lei Wu🇨🇳 · Jason Yue🇹🇼

    We utilise the LHC Run-1 and -2 Higgs data to constrain the CP-violating top-Higgs couplings. In order to satisfy the current full Higgs data sets at $2\sigma$ level, the CP-odd component $C_t^p$ and the CP-even component $C_t^s$ have to be within the ranges $|C_t^p|<0.37$ and $0.85<C_t^s<1.20$, respectively, which is stronger than the LHC Run-1 bound $|C_t^p|<0.54$ and $0.68<C_t^s<1.20$. With the new bound, we explore the impact on the CP-violating top-Higgs couplings in the Higgs production processes $pp\to t\bar{t}h,thj,hh$ at 13 TeV LHC, and $e^{+}{e}^{-}\to hZ,h\gamma$ at future 240 GeV Higgs factories. We find that the cross sections of $pp\to t\bar{t}h$, $pp\to thj$, $pp\to hh$, $e^{+}{e}^{-}\to hZ$ and $e^{+}{e}^{-}\to h\gamma$ can be enhanced up to 1.41, 1.18, 2.20, 1.001 and 1.09 times as large as the SM predictions, respectively. The future precision measurement of the process $e^{+}{e}^{-}\to h\gamma$ with an accuracy of 5\% will be able to constrain $|C_t^p|<0.19$ at most at a 240 GeV $e^{+}{e}^{-}$ Higgs factory.

    hep-phhep-exPRD(2017)·39 citations
12. 12*

    Study on the ${\rm Y}(1S)$ $\to$ $B_{c}M$ weak decays

    Junfeng Sun🇨🇳 · Lili Chen🇨🇳 · Na Wang🇨🇳 · Qin Chang🇨🇳 · Jinshu Huang🇨🇳 · Yueling Yang🇨🇳

    Motivated by the prospects of the potential ${\rm Y}(1S)$ particle at high-luminosity heavy-flavor experiments, we studied the ${\rm Y}(1S)$ $\to$ $B_{c}M$ weak decays, where $M$ $=$ $\pi$, $\rho$, $K^{(\ast )}$. The nonfactorizable contributions to hadronic matrix elements are taken into consideration with the QCDF approach. It is found that the CKM-favored ${\rm Y}(1S)$ $\to$ $B_c\rho$ decay has branching ratio of $\mathcal{O}(10^{-10})$, which might be measured promisingly by the future experiments.

    hep-phAdv.High Energy Phys.(2015)·9 citations
13. 13*

    Study on ${\rm Y}(nS)$ $\to$ $B_{c}M$ decays

    Junfeng Sun🇨🇳 · Lili Chen🇨🇳 · Na Wang🇨🇳 · Jinshu Huang🇨🇳 · Yueling Yang🇨🇳 · Qin Chang🇨🇳

    With anticipation of abundant Upsilons data sample at high-luminosity heavy-flavor experiments in the future, we studied nonleptonic two-body weak decays of ${\rm Y}(nS)$ below the open-bottom threshold with $n$ $=$ $1$, $2$ and $3$. It is found that branching ratios for ${\rm Y}(1S,2S,3S)$ $\to$ $B_c\rho$ decays are relatively large among upsilons decay into $B_{c}M$ final states ($M$ $=$ $\pi$ $\rho$, $K$ and $K^{\ast }$) and can reach up to $10^{-10}$, which is promisingly detected by experiments at the running LHC and forthcoming SuperKEKB.

    hep-phJ.Phys.G(2015)·7 citations
14. 14*

    Two-pole structure of the $D_0^{\ast }(2400)$

    Miguel Albaladejo🇪🇸 · Pedro Fernandez-Soler🇪🇸 · Feng-Kun Guo🇨🇳 · Juan Nieves🇪🇸

    The so far only known charmed non-strange scalar meson is dubbed as $D_0^{\ast }(2400)$ in the Review of Particle Physics. We show, within the framework of unitarized chiral perturbation theory, that there are in fact two $(I=1/2,J^P=0^{+})$ poles in the region of the $D_0^{\ast }(2400)$ in the coupled-channel $D\pi$, $D\eta$ and $D_s\bar{K}$ scattering amplitudes. With all the parameters previously fixed, we predict the energy levels for the coupled-channel system in a finite volume, and find that they agree remarkably well with recent lattice QCD calculations. This successful description of the lattice data is regarded as a strong evidence for the two-pole structure of the $D_0^{\ast }(2400)$. With the physical quark masses, the poles are located at $\left(2105_{-8}^{+6}-i102_{-12}^{+10}\right)$~MeV and $\left(2451_{-26}^{+36}-i134_{-8}^{+7}\right)$~MeV, with the largest couplings to the $D\pi$ and $D_s\bar{K}$ channels, respectively. Since the higher pole is close to the $D_s\bar{K}$ threshold, we expect it to show up as a threshold enhancement in the $D_s\bar{K}$ invariant mass distribution. This could be checked by high-statistic data in future experiments. We also show that the lower pole belongs to the same SU(3) multiplet as the $D_{s0}^{\ast }(2317)$ state. Predictions for partners in the bottom sector are also given.

    hep-phhep-latPLB(2017)·165 citations
15. 15*

    Effect of electromagnetic dipole dark matter on energy transport in the solar interior

    Ben Geytenbeek🇦🇺 · Soumya Rao🇦🇺 · Pat Scott🇬🇧 · Aldo Serenelli🇪🇸 · Aaron C Vincent🇬🇧 · Martin White🇦🇺 · Anthony G Williams🇦🇺

    In recent years, a revised set of solar abundances has led to a discrepancy in the sound-speed profile between helioseismology and theoretical solar models. Conventional solutions require additional mechanisms for energy transport within the Sun. Vincent et al. have recently suggested that dark matter with a momentum or velocity dependent cross section could provide a solution. In this work, we consider three models of dark matter with such cross sections and their effect on the stellar structure. In particular, the three models incorporate dark matter particles interacting through an electromagnetic dipole moment: an electric dipole, a magnetic dipole or an anapole. Each model is implemented in the \texttt{DarkStec} stellar evolution program, which incorporates the effects of dark matter capture and heat transport within the solar interior. We show that dark matter with an anapole moment of $\sim 1{\mathrm{GeV}}^{-2}$ or magnetic dipole moment of $\sim 10^{-3}{\mu }_p$ can improve the sound-speed profile, small frequency separations and convective zone radius with respect to the Standard Solar Model. However, the required dipole moments are strongly excluded by direct detection experiments.

    hep-phastro-ph.SRJCAP(2017)·27 citations
16. 16*

    Getting Stuck: Using Monosignatures to Test Highly Ionizing Particles

    Christoph Englert🇬🇧 · Joerg Jaeckel🇩🇪

    In this paper we argue that monojet and monophoton searches can be a sensitive test of very highly ionizing particles such as particles with charges $\gtrsim 150e$ and more generally particles that do not reach the outer parts of the detector. 8 TeV monojet data from the CMS experiment excludes such objects with masses in the range $\lesssim 650\text{GeV}$ and charges $\gtrsim 100e$. This nicely complements searches for highly ionizing objects at ALICE, ATLAS, CMS and LHCb. Expected improvements in these channels will extend the sensitivity range to $m\lesssim 750\text{GeV}$. This search strategy can directly be generalized to other particles that strongly interact with the detector material, such as e.g. magnetic monopoles.

    hep-phhep-exPLB(2017)·3 citations
17. 17*

    Electrical Conductivity of Quark-Gluon Plasma in Strong Magnetic Fields

    Koichi Hattori🇨🇳 · Daisuke Satow🇩🇪

    We compute the electrical conductivity of quark-gluon plasma in a strong magnetic field $B$ with quantum field theory at finite temperature using the lowest Landau level approximation. We provide the one-loop result arising from 1-to-2 scattering processes whose kinematics are satisfied by the (1+1) dimensional fermion dispersion relation. Due to the chirality conservation, the conductivity diverges in the massless limit, and is sensitive to the value of the current quark mass. As a result, we find that the conductivity along the direction of the magnetic field is quite large compared with the value at $B=0$, mainly because of the small value of the current quark mass. We show that the resummation of the ladder diagrams for the current-current correlator gives rise to only sub-leading contributions beyond the leading-log order, and thus verify our one-loop result at the leading-log accuracy. We also discuss possible implications for the relativistic heavy-ion collisions.

    hep-phnucl-thPRD(2016)·113 citations
18. 18*

    Longitudinal Conductivity in Strong Magnetic Field in Perturbative QCD: Complete Leading Order

    Koichi Hattori🇨🇳 · Shiyong Li🇺🇸 · Daisuke Satow🇩🇪 · Ho-Ung Yee🇺🇸

    We compute the longitudinal electrical conductivity in the presence of strong background magnetic field in complete leading order of perturbative QCD, based on the assumed hierarchy of scales ${\alpha }_{s}eB\ll (m_q^2,T^2)\ll eB$. We formulate an effective kinetic theory of lowest Landau level quarks with the leading order QCD collision term arising from 1-to-2 processes that become possible due to 1+1 dimensional Landau level kinematics. In small $m_q/T\ll 1$ regime, the longitudinal conductivity behaves as ${\sigma }_{zz}\sim e^2(eB)T/({\alpha }_s{m}_q^2\log (m_q/T))$, where the quark mass dependence can be understood from the chiral anomaly with the axial charge relaxation provided by a finite quark mass $m_q$. We also present parametric estimates for the longitudinal and transverse "color conductivities" in the presence of strong magnetic field, by computing dominant damping rates for quarks and gluons that are responsible for color charge transportation. We observe that the longitudinal color conductivity is enhanced by strong magnetic field, which implies that the sphaleron transition rate in perturbative QCD is suppressed by strong magnetic field due to the enhanced Lenz's law in color field dynamics.

    hep-phhep-thnucl-thPRD(2017)·108 citations
19. 19*

    Non-abelian factorisation for next-to-leading-power threshold logarithms

    D. Bonocore🇳🇱 · E. Laenen🇳🇱 · L. Magnea🇮🇹 · L. Vernazza🇬🇧 · C. D. White🇬🇧

    Soft and collinear radiation is responsible for large corrections to many hadronic cross sections, near thresholds for the production of heavy final states. There is much interest in extending our understanding of this radiation to next-to-leading power (NLP) in the threshold expansion. In this paper, we generalise a previously proposed all-order NLP factorisation formula to include non-abelian corrections. We define a non-abelian radiative jet function, organising collinear enhancements at NLP, and compute it for quark jets at one loop. We discuss in detail the issue of double counting between soft and collinear regions. Finally, we verify our prescription by reproducing all NLP logarithms in Drell-Yan production up to NNLO, including those associated with double real emission. Our results constitute an important step in the development of a fully general resummation formalism for NLP threshold effects.

    hep-phhep-thJHEP(2016)·122 citations
20. 20*

    A Clockwork Theory

    Gian F. Giudice🇨🇭 · Matthew McCullough🇨🇭

    The clockwork is a mechanism for generating light particles with exponentially suppressed interactions in theories which contain no small parameters at the fundamental level. We develop a general description of the clockwork mechanism valid for scalars, fermions, gauge bosons, and gravitons. This mechanism can be implemented with a discrete set of new fields or, in its continuum version, through an extra spatial dimension. In both cases the clockwork emerges as a useful tool for model-building applications. Notably, the continuum clockwork offers a solution to the Higgs naturalness problem, which turns out to be the same as in linear dilaton duals of Little String Theory. We also elucidate the similarities and differences of the continuum clockwork with large extra dimensions and warped spaces. All clockwork models, in the discrete and continuum, exhibit novel phenomenology with a distinctive spectrum of closely spaced resonances.

    hep-phhep-thJHEP(2017)·267 citations
21. 21*

    Status and Future of Nuclear Matrix Elements for Neutrinoless Double-Beta Decay: A Review

    Jonathan Engel🇺🇸 · Javier Menéndez🇯🇵

    The nuclear matrix elements that govern the rate of neutrinoless double beta decay must be accurately calculated if experiments are to reach their full potential. Theorists have been working on the problem for a long time but have recently stepped up their efforts as ton-scale experiments have begun to look feasible. Here we review past and recent work on the matrix elements in a wide variety of nuclear models and discuss work that will be done in the near future. Ab initio nuclear-structure theory, which is developing rapidly, holds out hope of more accurate matrix elements with quantifiable error bars.

    ↳ nucl-thhep-exhep-phnucl-exRept.Prog.Phys.(2017)·646 citations
22. 22*

    Two-Loop SL(2) Form Factors and Maximal Transcendentality

    Florian Loebbert🇩🇪 · Christoph Sieg🇩🇪 · Matthias Wilhelm🇩🇪 · Gang Yang🇨🇳

    Form factors of composite operators in the SL(2) sector of N=4 SYM theory are studied up to two loops via the on-shell unitarity method. The non-compactness of this subsector implies the novel feature and technical challenge of an unlimited number of loop momenta in the integrand's numerator. At one loop, we derive the full minimal form factor to all orders in the dimensional regularisation parameter. At two loops, we construct the complete integrand for composite operators with an arbitrary number of covariant derivatives, and we obtain the remainder functions as well as the dilatation operator for composite operators with up to three covariant derivatives. The remainder functions reveal curious patterns suggesting a hidden maximal uniform transcendentality for the full form factor. Finally, we speculate about an extension of these patterns to QCD.

    ↳ hep-thhep-phJHEP(2016)·42 citations
23. 23*

    Partonic structure of neutral pseudoscalars via two photon transition form factors

    Khepani Raya🇲🇽 · Minghui Ding🇨🇳 · Adnan Bashir🇲🇽 · Lei Chang🇨🇳 · Craig D. Roberts🇺🇸

    The $\gamma {\gamma }^{\ast }\to {\eta }_{c,b}$ transition form factors are computed using a continuum approach to the two valence-body bound-state problem in relativistic quantum field theory, and thereby unified with equivalent calculations of electromagnetic pion elastic and transition form factors. The resulting $\gamma {\gamma }^{\ast }\to {\eta }_c$ form factor, $G_{{\eta }_c}(Q^2)$, is consistent with available data: significantly, at accessible momentum transfers, $Q^2{G}_{{\eta }_c}(Q^2)$ lies well below its conformal limit. These observations confirm that the leading-twist parton distribution amplitudes (PDAs) of heavy-heavy bound-states are compressed relative to the conformal limit. A clear understanding of the distribution of valence-quarks within mesons thus emerges; a picture which connects Goldstone modes, built from the lightest-quarks in Nature, with systems containing the heaviest valence-quarks that can now be studied experimentally, and highlights basic facts about manifestations of mass within the Standard Model.

    ↳ nucl-thhep-exhep-lathep-ph+1PRD(2017)·68 citations
24. 24*

    Constraining axionlike particles using the distance-duality relation

    Prabhakar Tiwari🇮🇱

    One of the fundamental results used in observational cosmology is the distance duality relation (DDR), which relates the luminosity distance, $D_L$, with angular diameter distance, $D_A$, at a given redshift $z$. We employ the observed limits of this relation to constrain the coupling of axion like particles (ALPs) with photons. With our detailed $3D$ ALP-photon mixing simulation in standard $\Lambda$CDM universe and latest DDR limits observed in Holand \& Barros (2016) we limit the coupling constant $g_{\varphi }\le 6\times 10^{-13}Ge{V}^{-1}\left(\frac{nG}{⟨B{⟩}_{\mathrm{Mpc}}}\right)$ for ALPs of mass $\le 10^{-15}$ eV. The DDR observations can provide very stringent constraint on ALPs mixing in future. Also any deviation in DDR can be conventionally explained as photons decaying to axions or vice-versa.

    ↳ astro-ph.COhep-phPRD(2017)·17 citations
25. 25*

    Standard Model Background of the Cosmological Collider

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

    The inflationary universe can be viewed as a "Cosmological Collider" with energy of Hubble scale, producing very massive particles and recording their characteristic signals in primordial non-Gaussianities. To utilize this collider to explore any new physics at very high scales, it is a prerequisite to understand the background signals from the particle physics Standard Model. In this paper we describe the Standard Model background of the Cosmological Collider.

    ↳ hep-thastro-ph.COhep-phPRL(2017)·159 citations
26. 26*

    Summary of recent experimental results on strangeness production

    Alexander Kalweit🇨🇭

    This article summarises the highlights of the recent experimental findings on strangeness production presented at the 16th edition of the {\it International Conference on Strangeness in Quark Matter} in Berkeley. Results obtained by eight large experimental collaborations (ALICE, ATLAS, CMS, HADES, LHCb, NA-61, PHENIX, STAR) spanning a large range in centre-of-mass energy and a variety of collision systems were presented at the conference. The article does not aim at being a complete review, but rather at connecting the experimental highlights of the different collaborations and at pointing towards questions which should be addressed by these experiments in future.

    ↳ hep-exhep-phnucl-exJ.Phys.Conf.Ser.(2017)·3 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.