Tue·Apr 4, 2017Tuesday·April 4, 2017

1. 01*

   Phenomenological and Experimental Developments in Charm Physics: The WG7 Report from CKM 2016

   Giulia Casarosa🇩🇪 · Angelo Di Canto🇨🇭 · Ayan Paul🇮🇹

   We present an overview of recent developments in charm physics reported in the Working~Group~7 meetings of the CKM 2016 workshop. Progresses in experimental analysis and techniques were reported by LHCb, Belle, BABAR and BESIII along with projections for the future. Developments were also reported in the phenomenological extraction of both direct and indirect CP violation from data in two-, three- and four-body hadronic decays of the $D$ mesonic system.

   hep-phhep-exPoS(2017)·0 citations
2. 02*

   Tau energy loss and ultrahigh energy skimming tau neutrinos

   Yu Seon Jeong🇰🇷 · Minh Vu Luu🇺🇸 · Mary Hall Reno🇺🇸 · Ina Sarcevic🇺🇸

   We consider propagation of high energy earth-skimming taus produced in interactions of astrophysical tau neutrinos. For astrophysical tau neutrinos we take generic power-law flux, $E^{-2}$ and the cosmogenic flux initiated by the protons. We calculate tau energy loss in several approaches, such as dipole models and the phenomenological approach in which parameterization of the $F_2$ is used. We evaluate the tau neutrino charged-current cross section using the same approaches for consistency. We find that uncertainty in the neutrino cross section and in the tau energy loss partially compensate giving very small theoretical uncertainty in the emerging tau flux for distances ranging from $2$ km to $100$ km and for the energy range between $10^6$ GeV and $10^{11}$ GeV, focusing on energies above $10^8$ GeV. When we consider uncertainties in the neutrino cross section, inelasticity in neutrino interactions and the tau energy loss, which are not correlated, i.e. they are not all calculated in the same approach, theoretical uncertainty ranges from about $30\%$ and $60\%$ at $10^8$ GeV to about factors of 3.3 and 3.8 at $10^{11}$ GeV for the $E^{-2}$ flux and the cosmogenic flux, respectively, for the distance of 10 km rock. The spread in predictions significantly increases for much larger distances, e.g., $\sim 1,000$ km. Most of the uncertainty comes from the treatment of photonuclear interactions of the tau in transit through large distances. We also consider Monte Carlo calculation of the tau propagation and we find that the result for the emerging tau flux is in agreement with the result obtained using analytic approach. Our results are relevant to several experiments that are looking for skimming astrophysical taus, such as the Pierre Auger Observatory, HAWC and Ashra. We evaluate the aperture for the Auger and discuss briefly application to the the other two experiments.

   hep-phastro-ph.HEPRD(2017)·24 citations
3. 03*

   Experimental constraint on quark electric dipole moments

   Tianbo Liu🇺🇸 · Zhiwen Zhao🇺🇸 · Haiyan Gao🇺🇸

   The electric dipole moments (EDMs) of nucleons are sensitive probes of additional $\mathcal{C}\mathcal{P}$ violation sources beyond the standard model to account for the baryon number asymmetry of the universe. As a fundamental quantity of the nucleon structure, tensor charge is also a bridge that relates nucleon EDMs to quark EDMs. With a combination of nucleon EDM measurements and tensor charge extractions, we investigate the experimental constraint on quark EDMs, and its sensitivity to $\mathcal{C}\mathcal{P}$ violation sources from new physics beyond the electroweak scale. We obtain the current limits on quark EDMs as $1.27\times 10^{-24}e\cdot \mathrm{cm}$ for the up quark and $1.17\times 10^{-24}e\cdot \mathrm{cm}$ for the down quark at the scale of $4\mathrm{Ge}{\mathrm{V}}^2$. We also study the impact of future nucleon EDM and tensor charge measurements, and show that upcoming new experiments will improve the constraint on quark EDMs by about three orders of magnitude leading to a much more sensitive probe of new physics models.

   hep-phhep-exnucl-exnucl-thPRD(2018)·42 citations
4. 04*

   The sign of the dipole-dipole potential by axion exchange

   Ryuji Daido🇯🇵 · Fuminobu Takahashi🇯🇵

   We calculate a dipole-dipole potential between fermions mediated by a light pseudoscalar, axion, paying a particular attention to the overall sign. While the sign of the potential is physical and important for experiments to discover or constrain the axion coupling to fermions, there is often a sign error in the literature. The purpose of this short note is to clarify the sign issue of the axion-mediated dipole-dipole potential. As a by-product, we find a sign change of the dipole-dipole potenital due to the different spin of the mediating particle.

   hep-phastro-ph.COhep-exhep-thPLB(2017)·24 citations
5. 05*

   MMHT PDFs: updates and outlook

   L. A. Harland-Lang🇬🇧 · A. D. Martin🇬🇧 · R. Nathvani🇬🇧 · R. S. Thorne🇬🇧

   We present the latest results of studies within the MMHT PDF framework. We discuss the impact of the most recent ATLAS 7 TeV jet data, demonstrating that while a good fit can be achieved for individual jet rapidity bins, it is not possible to achieve a good description of the data when all bins are fitted. We examine the role that the experimental correlated systematic uncertainties play in this, and demonstrate that by simply decorrelating no more than two sources of error between rapidity bins a remarkably improved description of the data can be achieved. We then study the impact of NNLO corrections, showing that a mild decrease in the fit quality is produced. We also present the results of including new LHC $W$, $Z$, $W+c$ and $t\overline{t}$ data on the MMHT14 PDF set, showing that a marked decrease in the $s+\overline{s}$ uncertainty is in particular achieved. Finally, some discussion of the latest work towards the inclusion of the photon PDF within the MMHT framework is presented.

   hep-phActa Phys.Polon.B(2017)·7 citations
6. 06*

   Interpretation of the newly observed ${\Omega }_c^0$ resonances

   Wei Wang🇨🇳 · Rui-Lin Zhu🇨🇳

   We study the charmed and bottomed doubly strange baryons within the heavy-quark-light-diquark framework. The two strange quarks are assumed to lie in $S$ wave and thus their total spin is 1. We calculate the mass spectra of the $S$ and $P$ wave orbitally excited states and find the ${\Omega }_c^0(2695)$ and ${\Omega }_c^0(2770)$ fit well as the $S$ wave states of charmed doubly strange baryons. The five newly ${\Omega }_c^0(X)$ resonances observed by the LHCb Collaboration, i.e. ${\Omega }_c^0(3000)$, ${\Omega }_c^0(3050)$, ${\Omega }_c^0(3066)$, ${\Omega }_c^0(3090)$, and ${\Omega }_c^0(3119)$, can be interpreted as the $P$ wave orbitally excited states. In heavy quark effective theory, we analyze their decays into the ${\Xi }_c^{+}{K}^{-}$ and ${\Xi }_c^{\prime +}{K}^{-}$, and point out that decays of the five P-wave ${\Omega }_c^0$ states into the ${\Xi }_c^{+}{K}^{-}$ and ${\Xi }_c^{\prime +}{K}^{-}$ are suppressed by either heavy quark symmetry or phase space. The narrowness of the five newly observed ${\Omega }_c^0(X)$ states can then be naturally interpreted with heavy quark symmetry.

   hep-phhep-exPRD(2017)·95 citations
7. 07*

   The Elastic $q\bar{q}$ Cross Section in the Nambu--Jona-Lasinio Model

   Rafael Chapelle🇫🇷 · Joerg Aichelin🇫🇷 · Juan M. Torres-Rincon🇩🇪

   We discuss the quark masses and the elastic $q\bar{q}$ cross sections at finite chemical potential in the Nambu--Jona-Lasinio model. We comment the generic features of the cross sections as functions of the chemical potential, temperature and collision energy. Finally, we discuss their relevance in the construction of a relativistic transport model for heavy-ion collisions based on this effective Lagrangian.

   hep-phJ.Phys.Conf.Ser.(2017)·0 citations
8. 08*

   Gravitational wave from dark sector with dark pion

   Koji Tsumura🇯🇵 · Masatoshi Yamada🇩🇪 · Yuya Yamaguchi🇯🇵

   In this work, we investigate the spectra of gravitational waves produced by chiral symmetry breaking in dark quantum chromodynamics (dQCD) sector. The dark pion ($\pi$) can be a dark matter candidate as weakly interacting massive particle (WIMP) or strongly interacting massive particle (SIMP). For a WIMP scenario, we introduce the dQCD sector coupled to the standard model (SM) sector with classical scale invariance and investigate the annihilation process of the dark pion via the $2\pi \to 2\text{SM}$ process. For a SIMP scenario, we investigate the $3\pi \to 2\pi$ annihilation process of the dark pion as a SIMP using chiral perturbation theory. We find that in the WIMP scenario the gravitational wave background spectra can be observed by future space gravitational wave antennas. On the other hand, when the dark pion is the SIMP dark matter with the constraints for the chiral perturbative limit and pion-pion scattering cross section, the chiral phase transition becomes crossover and then the gravitational waves are not produced.

   hep-phastro-ph.HEgr-qcJCAP(2017)·64 citations
9. 09*

   Excited states of the Wick-Cutkosky model with the Nakanishi representation in the Light-Front framework

   R. Pimentel🇧🇷 · W. de Paula🇧🇷

   The Wick-Cutkosky model is investigated using the framework of the Nakanishi Perturbative Integral Representation projected in the Light-Front hyperplane for an s-wave amplitude. We developed a new technique based on sucessive integration by parts of the Nakanishi Representation which enabled us to transform one of the integrations into a sum. With a set of boundary conditions it was possible to guess the format of the solution, which was in fact a distribution. The eigenequations obtained were the same as the originals of Cutkosky \cite{CutPR54}. Finally, a numerical check confirmed that the final equation reproduce the same eigenvalues as the initial Bethe-Salpeter equation.

   hep-phmath-phmath.MPnucl-thFew Body Syst.(2016)·7 citations
10. 10*

    Jet mass fluctuations and fragmentation functions

    Karoly Urmossy🇵🇱

    The effect of jet mass fluctuations on the fragmentation process is examined in the framework of a statistical hadronisation model. In this model, the fragmentation scale Q is taken to be the virtuality of the leading parton, and jet mass fluctuations are accounted for through this quantity. The scale evolution of the model is treated in the phi^3 theory with leading-order splitting function and one-loop coupling.

    hep-phActa Phys.Polon.B(2017)·2 citations
11. 11*

    Quantum Numbers of Recently Discovered ${\Omega }_c^0$ Baryons from Lattice QCD

    M. Padmanath🇩🇪 · Nilmani Mathur🇮🇳

    We present the ground and excited state spectra of ${\Omega }_c^0$ baryons with spin up to 7/2 from lattice quantum chromodynamics with dynamical quark fields. Based on our lattice results, we predict the quantum numbers of five ${\Omega }_c^0$ baryons, which have recently been observed by the LHCb Collaboration. Our results strongly indicate that the observed states ${\Omega }_c(3000{)}^0$ and ${\Omega }_c(3050{)}^0$ have spin-parity $J^P=1/2^{-}$, the states ${\Omega }_c(3066{)}^0$ and ${\Omega }_c(3090{)}^0$ have $J^P=3/2^{-}$, whereas ${\Omega }_c(3119{)}^0$ is possibly a $5/2^{-}$ state.

    hep-phhep-exhep-latnucl-thPRL(2017)·117 citations
12. 12*

    Quantum Numbers of ${\Omega }_c$ States and Other Charmed Baryons

    Hai-Yang Cheng🇹🇼 · Cheng-Wei Chiang🇹🇼

    Possible spin-parity quantum numbers for excited charmed baryon resonances are discussed in this work. Our main results are: (i) Among the five newly observed ${\Omega }_c$ states, we have identified ${\Omega }_c(3090)$ and ${\Omega }_c(3119)$ with radially excited ${\frac{1}{2}}^{+}(2S)$ and ${\frac{3}{2}}^{+}(2S)$ states, respectively, and ${\Omega }_c(3000)$ with ${\frac{1}{2}}^{-}(1P)$ and $S=\frac{3}{2}$. The two states ${\Omega }_c(3050)$ and ${\Omega }_c(3066)$ form a $P$-wave $({\frac{3}{2}}^{-},{\frac{5}{2}}^{-})$ doublet. (ii) The widths of ${\Omega }_c(3066)$ and ${\Xi }_c^{\prime }(2930)$ are calculable within the framework of heavy hadron chiral perturbation theory. (iii) Since the width of ${\Omega }_{c0}({\frac{1}{2}}^{-})$ is of order 410 MeV, not all observed narrow ${\Omega }_c$ baryons can be identified with $1P$ states. (iv) For the antitriplet ${\Lambda }_c$ and ${\Xi }_c$ states, their Regge trajectories for the orbital excitations of ${\frac{1}{2}}^{-}$ and ${\frac{3}{2}}^{-}$ are parallel to each other. Based on this nice property of parallelism, we see that the highest state ${\Lambda }_c(2940)$ does not fit if its quantum numbers are ${\frac{3}{2}}^{-}$ as found by LHCb. We suggest that ${\Lambda }_c(2940{)}^{+}$ is most likely the ${\frac{1}{2}}^{-}(2P)$ state. (v) The charmed baryon ${\Sigma }_c(2800)$ cannot be a ${\frac{1}{2}}^{-}$ state; otherwise, its width will be over 400~MeV, too large compared to the measured one. (vi) In the study of Regge trajectories of ${\Xi }_c^{\prime }$ states, we find a missing state. It should have quantum numbers ${\frac{5}{2}}^{-}$ with a mass around 2920~MeV.

    hep-phhep-exPRD(2017)·93 citations
13. 13*

    Excited state mass spectra, Decay properties and Regge trajectories of charm and charm-strange mesons

    Virendrasinh Kher🇮🇳 · Nayneshkumar Devlani🇮🇳 · Ajay Kumar Rai🇮🇳

    The framework of phenomenological quark-antiquark potential (Coulomb plus linear confinement) model with the Gaussian wave function is used for detailed study of masses of the ground, orbitally and radially excited states of heavy-light $Q\overline{q}$, $\left(Q=c,q=u/d,s\right)$ mesons. We incorporate $\mathcal{O}(1/m)$ correction to the potential energy term and relativistic corrections to the kinetic energy term of the hamiltonian. The spin-hyperfine, the spin-orbit and the tensor interactions incorporating the effect of mixing are employed to obtained the pseudoscalar, the vector, radially and orbitally excited states meson masses. The Regge trajectories in the $(J,M^2)$ and $(n_r,M^2)$ planes for heavy-light meson are investigated with their corresponding parameters. Leptonic and radiative leptonic decay widths and corresponding branching ratios are computed. The mixing parameters are also estimated in the present work. Our predictions are in good agreement with experimental results as well as lattice and other theoretical models.

    hep-phCPC(2017)·47 citations
14. 14*

    Experimental signatures of hadron asymptotics at the LHC

    S.M. Troshin🇷🇺 · N.E. Tyurin🇷🇺

    We discuss experimental signatures relevant for the LHC domain of energies allowing to discriminate possible asymptotic modes of hadron interactions.

    hep-phInt.J.Mod.Phys.A(2017)·16 citations
15. 15*

    Some new aspects of quarkonia production at the LHC

    Antoni Szczurek🇵🇱 · Anna Cisek🇵🇱 · Wolfgang Schafer🇵🇱

    We discuss some different new aspects of $J/\psi$ meson production in exclusive, semi-exclusive and inclusive processes. We finish with a short discussion of double $J/\psi$ production. We point out some new results obtained recently by our group and discuss some open issues.

    hep-phActa Phys.Polon.B(2017)·7 citations
16. 16*

    Three-Body Decay of ${\Lambda }_c^{\ast }(2595)$ and ${\Lambda }_c^{\ast }(2625)$ with Consideration of ${\Sigma }_c(2455)\pi$ and ${\Sigma }_c^{\ast }(2520)\pi$ in Intermediate States

    A. J. Arifi🇯🇵 · H. Nagahiro🇯🇵 · A. Hosaka🇯🇵

    Three-body decay of charmed baryons ${\Lambda }_c^{\ast }(2595)$ and ${\Lambda }_c^{\ast }(2625)$ into ${\Lambda }_c\pi \pi$ are studied with effective Lagrangians in which the coupling constants are extracted from the non-relativistic quark model. We take into account sequential processes going through ${\Sigma }_c(2455)$ and ${\Sigma }_c^{\ast }(2520)$ in intermediate states. The total decay widths are sensitive to the coupling of ${\Lambda }_c^{\ast }$ with ${\Sigma }_c\pi$ open channel and to ${\Sigma }_c^{\ast }\pi$ closed channel. We find that ${\Lambda }_c^{\ast }(2595)$ and ${\Lambda }_c^{\ast }(2625)$ with $\lambda$ mode assignment can explain nicely the experimental data. We also show invariant mass distributions of ${\Lambda }_c^{\ast }(2595)$ and ${\Lambda }_c^{\ast }(2625)$ decays which are significantly different for various quark configurations.

    hep-phPRD(2017)·19 citations
17. 17*

    Modeling NNLO jet corrections with neural networks

    Stefano Carrazza🇨🇭

    We present a preliminary strategy for modeling multidimensional distributions through neural networks. We study the efficiency of the proposed strategy by considering as input data the two-dimensional next-to-next leading order (NNLO) jet k-factors distribution for the ATLAS 7 TeV 2011 data. We then validate the neural network model in terms of interpolation and prediction quality by comparing its results to alternative models.

    hep-phActa Phys.Polon.B(2017)·8 citations
18. 18*

    Extracting the top-quark running mass using $t\bar{t}$+1-jet events produced at the Large Hadron Collider

    J. Fuster🇪🇸 · A. Irles🇫🇷 · D. Melini🇪🇸 · P. Uwer🇩🇪 · M. Vos🇪🇸

    We present the calculation of the next-to-leading order QCD corrections for top-quark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the top-quark mass. The results are compared to measurements at the Large Hadron Collider run I. In particular, we determine the top-quark running mass from a fit of the theoretical results presented here to the LHC data.

    hep-phhep-exEPJC(2017)·42 citations
19. 19*

    Multi-parton interactions and rapidity gap survival probability in jet-gap-jet processes

    Izabela Babiarz🇵🇱 · Rafal Staszewski🇵🇱 · Antoni Szczurek🇵🇱

    We discuss an application of dynamical multi-parton interaction model, tuned to measurements of underlying event topology, for a description of destroying rapidity gaps in the jet-gap-jet processes at the LHC. We concentrate on the dynamical origin of the mechanism of destroying the rapidity gap. The cross section for jet-gap-jet is calculated within LL BFKL approximation. We discuss the topology of final states without and with the MPI effects. We discuss some examples of selected kinematical situations (fixed jet rapidities and transverse momenta) as distributions averaged over the dynamics of the jet-gap-jet scattering. The color-singlet ladder exchange amplitude for the partonic subprocess is implemented into the \textsc{Pythia 8} generator, which is then used for hadronisation and for the simulation of the MPI effects. Several differential distributions are shown and discussed. We present the ratio of cross section calculated with and without MPI effects as a function of rapidity gap in between the jets.

    hep-phPLB(2017)·15 citations
20. 20*

    Radiative symmetry breaking from interacting UV fixed points

    Steven Abel🇬🇧 · Francesco Sannino🇩🇰

    It is shown that the addition of positive mass-squared terms to asymptotically safe gauge-Yukawa theories with perturbative UV fixed points leads to calculable radiative symmetry breaking in the IR. This phenomenon, and the multiplicative running of the operators that lies behind it, is akin to the radiative symmetry breaking that occurs in the Supersymmetric Standard Model.

    hep-phhep-thPRD(2017)·44 citations
21. 21*

    Muon g-2 in MSSM Gauge Mediation Revisited

    Tsutomu T. Yanagida🇯🇵 · Norimi Yokozaki🇯🇵

    The Higgs boson of 125 GeV requires large stop masses, leading to the large $\mu$-parameter in most cases of gauge mediation. On the other hand, the explanation for the muon $g-2$ anomaly needs small slepton and neutralino/chargino masses. Such disparity in masses may be obtained from a mass splitting of colored and non-colored messenger fields. However, even if the required small slepton and neutralino/chargino masses are realized, all parameter regions consistent with the muon g-2 are excluded by the recent updated ATLAS result on the wino search in the case that the messenger fields are in $5+\bar{5}$ representations of SU(5). It is also revealed that the messenger fields in $10+\overline{10}$ or $24$ representation can not explain the muon g-2 anomaly. We show, giving a simple example model, that the above confliction is solved if there is an additional contribution to the Higgs soft mass which makes the $\mu$-parameter small. We also show that the required Higgs B-term for the electroweak symmetry breaking is consistently generated by radiative corrections from gaugino loops.

    hep-phhep-exPLB(2017)·21 citations
22. 22*

    A Tale of Two Portals: Testing Light, Hidden New Physics at Future $e^{+}{e}^{-}$ Colliders

    Jia Liu🇩🇪 · Xiao-Ping Wang🇩🇪 · Felix Yu (MITP, Johannes Gutenberg University Mainz)🇩🇪

    We investigate the prospects for producing new, light, hidden states at a future $e^{+}{e}^{-}$ collider in a Higgsed dark $U(1{)}_D$ model, which we call the Double Dark Portal model. The simultaneous presence of both vector and scalar portal couplings immediately modifies the Standard Model Higgsstrahlung channel, $e^{+}{e}^{-}\to Zh$, at leading order in each coupling. In addition, each portal leads to complementary signals which can be probed at direct and indirect detection dark matter experiments. After accounting for current constraints from LEP and LHC, we demonstrate that a future $e^{+}{e}^{-}$ Higgs factory will have unique and leading sensitivity to the two portal couplings by studying a host of new production, decay, and radiative return processes. Besides the possibility of exotic Higgs decays, we highlight the importance of direct dark vector and dark scalar production at $e^{+}{e}^{-}$ machines, whose invisible decays can be tagged from the recoil mass method.

    hep-phhep-exJHEP(2017)·48 citations
23. 23*

    Setting limits on Effective Field Theories: the case of Dark Matter

    F. Pobbe🇮🇹 · A. Wulzer🇨🇭 · M. Zanetti🇮🇹

    The usage of Effective Field Theories (EFT) for LHC new physics searches is receiving increasing attention. It is thus important to clarify all the aspects related with the applicability of the EFT formalism in the LHC environment, where the large available energy can produce reactions that overcome the maximal range of validity, i.e. the cutoff, of the theory. We show that this does forbid to set rigorous limits on the EFT parameter space through a modified version of the ordinary binned likelihood hypothesis test, which we design and validate. Our limit-setting strategy can be carried on in its full-fledged form by the LHC experimental collaborations, or performed externally to the collaborations, through the Simplified Likelihood approach, by relying on certain approximations. We apply it to the recent CMS mono-jet analysis and derive limits on a Dark Matter (DM) EFT model. DM is selected as a case study because the limited reach on the DM production EFT Wilson coefficient and the structure of the theory suggests that the cutoff might be dangerously low, well within the LHC reach. However our strategy can also be applied to EFT's parametrising the indirect effects of heavy new physics in the Electroweak and Higgs sectors.

    hep-phhep-exJHEP(2017)·23 citations
24. 24*

    Numerical calculation of the decay widths, the decay constants, and the decay energy spectra of the resonances of the delta-shell potential

    Rafael de la Madrid🇺🇸

    We express the resonant energies of the delta-shell potential in terms of the Lambert $W$ function, and we calculate their decay widths and decay constants. The ensuing numerical results strengthen the interpretation of such decay widths and constants as a way to quantify the coupling between a resonance and the continuum. We calculate explicitly the decay energy spectrum of the resonances of the delta-shell potential, and we show numerically that the lineshape of such spectrum is not the same as, and can be very different from, the Breit-Wigner (Lorentzian) distribution. We argue that the standard Golden Rule cannot describe the interference of two resonances, and we show how to describe such interference by way of the decay energy spectrum of two resonant states.

    ↳ quant-phhep-phnucl-thNPA(2017)·16 citations
25. 25*

    Peeking into the Origins of IceCube Neutrinos: I. Buried Transient TeV Miniburst Rates

    Matthew D. Kistler (KIPAC, Stanford, SLAC)🇺🇸 · Hasan Yuksel (Mimar Sinan)🇹🇷

    Any interpretation of the astrophysical neutrinos discovered by IceCube must accommodate a variety of multimessenger constraints. We address implications of these neutrinos being produced in transient sources, principally if buried within supernovae so that gamma rays are absorbed by the star. This would alleviate tension with the isotropic Fermi GeV background that >10 TeV neutrinos rival in detected energy flux. We find that IceCube data constrain transient properties, implying buried GeV-TeV electromagnetic emission near or exceeding canonical SN explosion energies of ~10^51 erg, indicative of an origin within superluminous SNe. TeV neutrino bursts with dozens of IceCube events -- which would be of great use for understanding r-process nucleosynthesis and more -- may be just around the corner if they are a primary component of the flux.

    ↳ astro-ph.HEastro-ph.COastro-ph.GAhep-ph+12 citations
26. 26*

    Evaluating $V_{ud}$ from neutron beta decays

    Dinko Pocanic🇺🇸

    Although well studied, the neutron still offers a unique laboratory for precise tests of Standard Model (SM) predictions. Neutron decay is free of nuclear structure corrections present in nuclear beta decays, and, with a $10^8$ times larger branching ratio than the theoretically cleaner pion beta decay, it is more readily accessible to experimental study than the latter. Measurements at sufficient precision of the neutron lifetime, and of correlations in free neutron beta decay, offer several stringent tests of the SM, including the weak quark couplings (quark-lepton universality), and certain extensions beyond the standard $V-A$ weak interaction theory. This paper focuses on the long-running free neutron beta decay experimental program aimed at obtaining an independent determination of the Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix element $V_{ud}$. We discuss the present state of precision achieved in this program and briefly review the currently active projects, as well as the expected near-term improvements in the field.

    ↳ nucl-exhep-phPoS(2017)·2 citations
27. 27*

    Nuclear Effects in the Deuteron and Constraints on the d/u Ratio

    S.I. Alekhin🇷🇺 · S.A. Kulagin🇷🇺 · R. Petti🇺🇸

    We present a detailed study of nuclear corrections in the deuteron (D) by performing an analysis of data from deep inelastic scattering off proton and D, dilepton pair production in $pp$ and pD interactions, and W^+- and Z boson production in pp and p pbar collisions. In particular, we discuss the determination of the off-shell function describing the modification of the parton distribution functions in bound nucleons in the context of global QCD fits. Our results are consistent with the ones obtained independently from the study of deep inelastic scattering data off heavy nuclei with $A\ge 4$, further confirming the universality of the off-shell function. We also study the sensitivity to the modeling of the deuteron wave function. As an important application we discuss the impact of nuclear corrections to the deuteron on the determination of the d quark distribution.

    ↳ nucl-thhep-phPRD(2017)·54 citations
28. 28*

    Multipole scattering amplitudes in the Color Glass Condensate formalism

    Yu Shi🇨🇳 · Enke Wang🇨🇳 · Cheng Zhang🇨🇳

    We evaluate the octupole in the large-$N_c$ limit in the McLerran-Venugopalan model, and derive a general expression of the 2n-point correlator, which can be applied in analytical studies of the multi-particle production in the scatterings between hard probes and dense targets.

    ↳ hep-thhep-phPRD(2017)·17 citations
29. 29*

    Proton distributions in $dp$ dielectron production within Regge theory

    A.P.Jerusalimov🇷🇺 · G.I.Lykasov🇷🇺

    The processes of dielectron production in deuteron-proton collisions at intermediate incident deuteron beam energies are analyzed in the spectator model within the one-pion exchange reggeized approach. We focus mainly on the momentum and angle distributions of the proton-spectator and the proton emitted in quasi-free $NN$ processes at small angles in the laboratory frame. It is shown that the inclusion of many channels in quasi-free $NN$ interaction allows us to describe the HADES data quite satisfactorily at incident deuteron kinetic energies of about 2.5 GeV.

    ↳ nucl-thhep-phInt.J.Mod.Phys.A(2017)·2 citations
30. 30*

    Fluids, Superfluids and Supersolids: Dynamics and Cosmology of Self Gravitating Media

    Marco Celoria🇮🇹 · Denis Comelli🇮🇹 · Luigi Pilo🇮🇹

    We compute cosmological perturbations for a generic self-gravitating media described by four derivatively- coupled scalar fields. Depending on the internal symmetries of the action for the scalar fields, one can describe perfect fluids, superfluids, solids and supersolids media. Symmetries dictate both dynamical and thermodynamical properties of the media. Generically, scalar perturbations include, besides the gravitational potential, an additional non-adiabatic mode associated with the entropy per particle {\sigma}. While perfect fluids and solids are adiabatic with {\sigma} constant in time, superfluids and supersolids feature a non-trivial dynamics for {\sigma}. Special classes of isentropic media with zero {\sigma} can also be found. Tensor modes become massive for solids and supersolids. Such an effective approach can be used to give a very general and symmetry driven modelling of the dark sector.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2017)·34 citations
31. 31*

    Implications of a frame dependent gravitational effective action for perturbations on the Robertson-Walker Metric

    Stephen L. Adler🇺🇸

    In earlier work we showed that a frame dependent effective action motivated by the postulates of three-space general coordinate invariance and Weyl scaling invariance exactly mimics a cosmological constant in Robertson-Walker (RW) spacetimes. Here we study the implications of this effective action for small fluctuations around a spatially flat RW background geometry. The equations for the conserving extension of the modified stress-energy tensor can be integrated in closed form, and involve only the metric perturbation $h_{00}$. Hence the equations for tensor and vector perturbations are unmodified, but there are Hubble scale additions to the scalar perturbation equations, which nonetheless admit no propagating wave solutions. Consequently, there are no modifications to standard gravitational wave propagation theory, but there may be observable implications for cosmology. We give a self-contained discussion, including an analysis of the restricted class of gauge transformations that act when a frame dependent effective action is present.

    ↳ gr-qcastro-ph.COhep-phhep-thInt.J.Mod.Phys.D(2017)·7 citations
32. 32*

    Proton Cumulants and Correlation Functions in Au + Au Collisions at $\sqrt{s_{\mathrm{NN}}}$=7.7-200 GeV from UrQMD Model

    Shu He🇨🇳 · Xiaofeng Luo🇨🇳

    We studied the acceptance dependence of proton cumulants (up to fourth order) and correlation functions in 0--5\% most central Au+Au collisions at $\sqrt{s_{\text{NN}}}$=7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV from UrQMD model. We found that high order proton cumulants show suppressions at large acceptance. By decomposing the proton cumulants into linear combination of multi-proton correlation functions, we observed the two-proton correlation functions always show negative values due to the effects of baryon number conservations. The three and four-proton correlation functions are close to zero and show negligible acceptance dependence. We further observed that the proton cumulants and correlation functions follow similar trends and show a scaling behavior when plotting the results versus mean number of protons. The comparisons between experimental data and the UrQMD calculations show that the non-monotonic energy dependence of proton correlation functions measured by STAR experiment cannot be described by the UrQMD model. The UrQMD calculations can provide us baselines for the experimental studies of the proton cumulants and correlation functions. Finally, we propose to measure the rapidity dependence of the reduced proton correlation functions to search for the QCD critical point in heavy-ion collisions.

    ↳ nucl-exhep-exhep-phnucl-thPLB(2017)·38 citations
33. 33*

    One-particle reducible contribution to the one-loop scalar propagator in a constant field

    James P. Edwards🇲🇽 · Christian Schubert🇲🇽

    Recently, Gies and Karbstein showed that the two-loop Euler-Heisenberg Lagrangian receives a finite one-particle reducible contribution in addition to the well-known one-particle irreducible one. Here, we demonstrate that a similar contribution exists for the propagator in a constant field already at the one-loop level, and we calculate this contribution for the scalar QED case. We also present an independent derivation of the Gies-Karbstein result using the worldline formalism, treating the scalar and spinor QED cases in a unified manner.

    ↳ hep-thastro-ph.HEhep-phNPB(2017)·33 citations
34. 34*

    First measurement of transverse-spin-dependent azimuthal asymmetries in the Drell-Yan process

    Aghasyan · R. Akhunzyanov · M.G. Alexeev · G.D. Alexeev · A. Amoroso · V. Andrieux · N.V. Anfimov · V. Anosov · A. Antoshkin · K. Augsten · W. Augustyniak · A. Austregesilo and 208 other authors

    The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190 GeV/$c$, ${\pi }^{-}$ beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3 GeV/$c^2$ and 8.5 GeV/$c^2$. The observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of Quantum Chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. These DY results are obtained at a hard scale comparable to that of a recent COMPASS SIDIS measurement and hence allow unique tests of fundamental QCD universality predictions.

    ↳ hep-exhep-phPRL(2017)·171 citations
35. 35*

    Ambitwistor strings and reggeon amplitudes in N=4 SYM

    L.V.Bork🇷🇺 · A.I.Onishchenko🇷🇺

    We consider the description of reggeon amplitudes (Wilson lines form factors) in N=4 SYM within the framework of four dimensional ambitwistor string theory. The latter is used to derive scattering equations representation for reggeon amplitudes with multiple reggeized gluons present. It is shown, that corresponding tree-level string correlation function correctly reproduces previously obtained Grassmannian integral representation of reggeon amplitudes in N=4 SYM.

    ↳ hep-thhep-phPLB(2017)·4 citations
36. 36*

    Cosmic microwave background constraints on secret interactions among sterile neutrinos

    Francesco Forastieri🇮🇹 · Massimiliano Lattanzi🇮🇹 · Gianpiero Mangano🇮🇹 · Alessandro Mirizzi🇮🇹 · Paolo Natoli🇮🇹 · Ninetta Saviano🇩🇪

    Secret contact interactions among eV sterile neutrinos, mediated by a massive gauge boson $X$ (with $M_X\ll M_W$), and characterized by a gauge coupling $g_X$, have been proposed as a mean to reconcile cosmological observations and short-baseline laboratory anomalies. We constrain this scenario using the latest Planck data on Cosmic Microwave Background anisotropies, and measurements of baryon acoustic oscillations (BAO). We consistently include the effect of secret interactions on cosmological perturbations, namely the increased density and pressure fluctuations in the neutrino fluid, and still find a severe tension between the secret interaction framework and cosmology. In fact, taking into account neutrino scattering via secret interactions, we derive our own mass bound on sterile neutrinos and find (at 95% CL) $m_s<0.82$ eV or $m_s<0.29$ eV from Planck alone or in combination with BAO, respectively. These limits confirm the discrepancy with the laboratory anomalies. Moreover, we constrain, in the limit of contact interaction, the effective strength $G_X$ to be $<2.8(2.0)\times 10^{10}{G}_F$ from Planck (Planck+BAO). This result, together with the mass bound, strongly disfavours the region with $M_X\sim 0.1$ MeV and relatively large coupling $g_X\sim 10^{-1}$, previously indicated as a possible solution to the small scale dark matter problem.

    ↳ astro-ph.COhep-phJCAP(2017)·66 citations
37. 37*

    $|V_{cb}|$ using lattice QCD

    Matthew Wingate🇬🇧

    Lattice QCD calculations of hadronic matrix elements allow one to draw inferences about quark flavor interactions from measurements of hadron decays. Within the context of the Standard Model, the magnitude of the charm-bottom quark coupling $V_{cb}$ can be determined from semileptonic decays such as $B\to D^{(\ast )}\ell \nu$. This brief review summarizes the present status and short-term outlook for determining $|V_{cb}|$ using lattice QCD.

    ↳ hep-lathep-phPoS(2017)·2 citations
38. 38*

    Motivations for AdS/QCD from 10D supergravity solutions

    Wayne de Paula🇧🇷

    We discuss some attempts for the construction of gravity duals of QCD-like theories. It is analysed some properties of solutions of 10D Type IIB supergravity theory that attempt to be dual to $\mathcal{N}$=1 gauge theories, in particular the solutions that belong to Papadoulos-Tseytlin ansatz. We argue that one could obtain 5D effective theories from 10d solutions and it motivates the use of phenomenological AdS/QCD models.

    ↳ hep-thgr-qchep-phJ.Phys.Conf.Ser.(2016)·0 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.