Wed·Nov 1, 2017Wednesday·November 1, 2017

1. 01*

   A Cosmological Signature of the Standard Model Higgs Vacuum Instability: Primordial Black Holes as Dark Matter

   J. R. Espinosa🇪🇸 · D. Racco🇨🇭 · A. Riotto🇨🇭

   For the current central values of the Higgs and top masses, the Standard Model Higgs potential develops an instability at a scale of the order of $10^{11}$ GeV. We show that a cosmological signature of such instability could be dark matter in the form of primordial black holes seeded by Higgs fluctuations during inflation. The existence of dark matter might not require physics beyond the Standard Model.

   hep-phastro-ph.COgr-qchep-thPRL(2018)·142 citations
2. 02*

   Composite Higgs models in disguise

   Jack Setford🇬🇧

   We present a mechanism for disguising one composite Higgs model as another. Allowing the global symmetry of the strong sector to be broken by large mixings with elementary fields, we show that we can disguise one coset $\mathcal{G}/\mathcal{H}$ such that at low energies the phenomenology of the model is better described with a different coset ${\mathcal{G}}^{\prime }/{\mathcal{H}}^{\prime }$. Extra scalar fields acquire masses comparable to the rest of the strong sector resonances and therefore are no longer considered pNGBs. Following this procedure we demonstrate that two models with promising UV-completions can be disguised as the more minimal $SO(5)/SO(4)$ coset.

   hep-phJHEP(2018)·7 citations
3. 03*

   The non-diffractive pp cross-section and Survival Probabilities at LHC

   G. Pancheri🇮🇹 · A. Grau🇪🇸 · Y.N. Srivastava🇺🇸 · D.A. Fagundes🇧🇷 · O. Shekhovtsova🇵🇱

   We present an estimate of survival probability from an eikonal mini- jet model implemented with a proposal for soft gluon resummation to all orders. We compare it with experimental data for diffractive di-jet production from LHC experiments, CMS and ATLAS, both at LO and NLO order.

   hep-ph0 citations
4. 04*

   New method of galactic axion search

   M. Yoshimura🇯🇵 · N. Sasao🇯🇵

   An appealing candidate of the galactic dark matter is the axion, which was postulated to solve the strong CP (Charge-conjugation Parity) violation problem in the standard particle theory. A new experimental method is proposed to determine the axion mass. The method uses collectively and coherently excited atoms or molecules, the trigger laser inducing galactic axion absorption along with signal photon emission to be detected.

   hep-phastro-ph.GAhep-exphysics.atom-phEPJC(2018)·7 citations
5. 05*

   Collider Detection of Dark Matter Electromagnetic Anapole Moments

   Alexandre Alves🇧🇷 · A. C. O. Santos🇧🇷 · Kuver Sinha🇺🇸

   Dark matter that interacts with the Standard Model by exchanging photons through higher multipole interactions occurs in a wide range of both strongly as well as weakly coupled hidden sector models. We study the collider detection prospects of these candidates, with a focus on Majorana dark matter that couples through the anapole moment. The study is conducted at the effective field theory level with the mono-$Z$ signature incorporating varying levels of systematic uncertainties at the high-luminosity LHC. The projected collider reach on the anapole moment is then compared to the reach coming from direct detection experiments like LZ. Finally, the analysis is applied to a weakly coupled completion with leptophilic dark matter.

   hep-phPRD(2018)·21 citations
6. 06*

   Scalar one-loop Feynman integrals with complex internal masses revisited

   K. H. Phan🇻🇳 · T. N. H. Pham🇻🇳

   In this paper, we study systematically scalar one-loop two-, three-, and four-point Feynman integrals with complex internal masses. Our analytic results presented in this report are valid for both real and complex internal masses. The calculations are then implemented into a {\tt Mathematica} (version $9$) package and {\tt FORTRAN} program. Our program is cross-checked numerically with {\tt LoopTools} (version $2.14$) in real as well as complex internal masses. We find a perfect agreement between our results and {\tt LoopTools} for all cases. Additionally, this work is applied for evaluating scalar one-loop Feynman integrals developed leading Landau singularities which may appear in real scattering processes at colliders. Last but not least, the method used in this report can also extend to evaluate tensor one-loop integrals. Therefore, this may open a new approach which can solve the inverse Gram determinant problem analytically.

   hep-ph3 citations
7. 07*

   Photoproduction of $J/\psi$ with dissociation of protons

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

   We present the cross sections for both electromagnetic and diffractive dissociation of protons for semiexclusive production of $J/\psi$ mesons in proton-proton collisions at the LHC. Differential distributions in missing mass ($M_X$), as well as distributions in rapidity and transverse momentum of the $J/\psi$ are calculated for $\sqrt{s}=7$ TeV and 13 TeV proton proton collisions. We compare the distributions for purely electromagnetic and purely diffractive proton excitations/dissociation. We predict cross sections for electromagnetic and diffractive excitations of similar order of magnitude.

   hep-ph0 citations
8. 08*

   Exotic Lepton Searches via Bound State Production at the LHC

   Neil D. Barrie🇦🇺 · Archil Kobakhidze🇦🇺 · Shelley Liang🇦🇺 · Matthew Talia🇦🇺 · Lei Wu🇨🇳

   Heavy long-lived multi-charged leptons (MCLs) are predicted by various new physics models. These hypothetical MCLs can form bound states, due to their high electric charges and long life times. In this work, we propose a novel strategy of searching for MCLs through their bound state productions and decays. By utilizing LHC-8 TeV data in searching for resonances in the diphoton channel, we exclude the masses of isospin singlet heavy leptons with electric charge $|q|\ge 6$ (in units of electron charge) lower than $\sim$1.2 TeV, which are much stronger than the corresponding 8 TeV LHC bounds from analysing the high ionisation and the long time-of-flight of MCLs. By utilising the current 13 TeV LHC diphoton channel measurements the bound can further exclude MCL masses up to $\sim$1.6 TeV for $|q|\ge 6$. Also, we demonstrate that the conventional LHC limits from searching for MCLs produced via Drell-Yan processes can be enhanced by including the contribution of photon fusion processes.

   hep-phPLB(2018)·9 citations
9. 09*

   Probing new intra-atomic force with isotope shifts

   Kyoko Mikami🇯🇵 · Minoru Tanaka🇯🇵 · Yasuhiro Yamamoto🇰🇷

   In the development of atomic clocks, some atomic transition frequencies are measured with remarkable precision. These measured spectra may include effects of a new force mediated by a weakly interacting boson. Such effects might be distilled out from possible violation of a linear relation in isotope shifts between two transitions, as known as King's linearity, with relatively suppressed theoretical uncertainties. We discuss the experimental sensitivity to a new force in the test of the linearity as well as the linearity violation owing to higher order effects within the Standard Model. The sensitivity to new physics is limited by such effects. We have found that for Yb${}^{+}$, the higher order effect is in the reach of future experiments. The sensitivity to a heavy mediator is also discussed. It is analytically clarified that the sensitivity becomes weaker than that in the literature. Our numerical results of the sensitivity are compared with other weak force search experiments.

   hep-phEPJC(2017)·34 citations
10. 10*

    A study of $\rho -\omega$ mixing in resonance chiral theory

    Yun-Hua Chen🇨🇳 · De-Liang Yao🇪🇸 · Han-Qing Zheng🇨🇳

    The strong and electromagnetic corrections to $\rho -\omega$ mixing are calculated using a SU(2) version of resonance chiral theory up to next-to-leading orders in $1/N_C$ expansion, respectively. Up to our accuracy, the effect of the momentum dependence of $\rho -\omega$ mixing is incorporated due to the inclusion of loop contributions. We analyze the impact of $\rho -\omega$ mixing on the pion vector form factor by performing numerical fit to the data extracted from $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ and $\tau \to {\nu }_{\tau }2\pi$, while the decay width of $\omega \to {\pi }^{+}{\pi }^{-}$ is taken into account as a constraint. It is found that the momentum dependence is significant in a good description of the experimental data. In addition, based on the fitted values of the involved parameters, we analyze the decay width of $\omega \to {\pi }^{+}{\pi }^{-}$, which turns out to be highly dominated by the $\rho -\omega$ mixing effect.

    hep-phhep-exnucl-thCommun.Theor.Phys.(2018)·11 citations
11. 11*

    Production of two $J/\psi$ mesons in proton-proton collisions at the LHC

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

    We discuss inclusive production of pairs of $J/\psi$ quarkonia. Both leading-order single parton (box) contribution and double-parton contributions are included. In addition we discuss a contribution of higher-order two-gluon exchange and a feed down from double ${\chi }_c$ production. The second two contributions are important for large rapidity distance between the two $J/\psi$ mesons and for relatively large cut-offs on quarkonia transverse momenta. A relation to current experiments is discussed.

    hep-ph2 citations
12. 12*

    On-the-fly reduction of open loops

    Federico Buccioni🇨🇭 · Stefano Pozzorini🇨🇭 · Max Zoller🇨🇭

    Building on the open-loop algorithm we introduce a new method for the automated construction of one-loop amplitudes and their reduction to scalar integrals. The key idea is that the factorisation of one-loop integrands in a product of loop segments makes it possible to perform various operations on-the-fly while constructing the integrand. Reducing the integrand on-the-fly, after each segment multiplication, the construction of loop diagrams and their reduction are unified in a single numerical recursion. In this way we entirely avoid objects with high tensor rank, thereby reducing the complexity of the calculations in a drastic way. Thanks to the on-the-fly approach, which is applied also to helicity summation and for the merging of different diagrams, the speed of the original open-loop algorithm can be further augmented in a very significant way. Moreover, addressing spurious singularities of the employed reduction identities by means of simple expansions in rank-two Gram determinants, we achieve a remarkably high level of numerical stability. These features of the new algorithm, which will be made publicly available in a forthcoming release of the OpenLoops program, are particularly attractive for NLO multi-leg and NNLO real-virtual calculations.

    hep-phEPJC(2018)·229 citations
13. 13*

    New theoretical results in ultrarelativistic ultraperipheral lead-lead collisions

    Mariola Klusek-Gawenda🇵🇱 · Antoni Szczurek🇵🇱

    We study dilepton, proton-antiproton and diphoton production in ultraperipheral lead-lead collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 and 5.5 TeV. The nuclear calculations are based on equivalent photon approximation in the impact parameter space. For correct description of the $\gamma \gamma \to p\bar{p}$ Belle data we include the proton-exchange, the $f_2(1270)$ and $f_2(1950)$ s-channel exchanges, as well as the handbag mechanism. For four muon production, we take into account electromagnetic (two-photon) double-scattering production and direct $\gamma \gamma$ production of four muons in one scattering. The cross sections for elementary $\gamma \gamma \to \gamma \gamma$ subprocess are calculated including three different mechanisms: box diagrams with leptons and quarks in the loops, a VDM-Regge contribution with virtual intermediate hadronic excitations of the photons and the two-gluon exchange contribution. We find that the cross section for elastic $\gamma \gamma$ scattering could be measured in the lead-lead collisions for the diphoton invariant mass up to $W_{\gamma \gamma }\approx$ 15 - 20 GeV. Our Standard Model predictions are compared with a recent ATLAS experimental result. We discuss results for PbPb$\to$PbPb${\mu }^{+}{\mu }^{-}{\mu }^{+}{\mu }^{-}$, PbPb$\to$PbPb$e^{+}{e}^{-}{e}^{+}{e}^{-}$, PbPb$\to$PbPb$p\bar{p}$ and PbPb$\to$PbPb$\gamma \gamma$ reactions at LHC energy.

    hep-phnucl-th0 citations
14. 14*

    Multiple interactions and rapidity gap survival

    V.A. Khoze🇬🇧 · A.D. Martin🇬🇧 · M.G. Ryskin🇬🇧

    Observations of rare processes containing large rapidity gaps at high energy colliders may be exceptionally informative. However the cross sections of these events are small in comparison with that for the inclusive processes since there is a large probability that the gaps may be filled by secondary particles arising from additional soft interactions or from gluon radiation. Here we review the calculations of the probability that the gaps survive population by particles from these effects for a wide range of different processes.

    hep-phJ.Phys.G(2018)·40 citations
15. 15*

    P-wave excited $B_c^{\ast \ast }$ meson photoproduction at the LHeC

    He Kai🇨🇳 · Bi Huan-Yu🇨🇳 · Zhang Ren-You🇨🇳 · Li Xiao-Zhou🇨🇳 · Ma Wen-Gan🇨🇳

    As an important sequential work of the S-wave $B_c^{(\ast )}$ (${}^1{S}_0{(}^3{S}_1)$) meson production at the large hadron electron collider (LHeC), we investigate the production of the P-wave excited $B_c^{\ast \ast }$ states (${}^1{P}_1$ and ${}^3{P}_J$ with $J=0,1,2$) via photoproduction mechanism within the framework of nonrelativistic QCD at the LHeC. Generally, the $e^{-}+P\to \gamma +g\to B_c^{\ast \ast }+b+\bar{c}$ process is considered as the main production mechanism at an electron-proton collider due to the large luminosity of the gluon. However, according to our experience on the S-wave $B_c^{(\ast )}$ meson production at the LHeC, the extrinsic production mechanism, i.e., $e^{-}+P\to \gamma +c\to B_c^{\ast \ast }+b$ and $e^{-}+P\to \gamma +\bar{b}\to B_c^{\ast \ast }+\bar{c}$, could also provide dominating contributions at low $p_T$ region. A careful treatment between these channels is performed and the results on total and differential cross sections, together with main uncertainties are discussed. Taking the quark masses $m_b=4.90\pm 0.40$ GeV and $m_c=1.50\pm 0.20$ GeV into account and summing up all the production channels, we expect to accumulate $(2.48_{-1.75}^{+3.55})\times 10^4$ $B_c^{\ast \ast }({}^1{P}_1)$, $(1.14_{-0.82}^{+1.49})\times 10^4$ $B_c^{\ast \ast }({}^3{P}_0)$, $(2.38_{-1.74}^{+3.39})\times 10^4$ $B_c^{\ast \ast }({}^3{P}_1)$ and $(5.59_{-3.93}^{+7.84})\times 10^4$ $B_c^{\ast \ast }({}^3{P}_2)$ events at the $\sqrt{S}=1.30\mathrm{TeV}$ LHeC in one operation year with luminosity $\mathcal{L}=10^{33}$ cm${}^{-2}$s${}^{-1}$. With such sizable events, it is worth studying the properties of excited P-wave $B_c^{\ast \ast }$ states at the LHeC.

    hep-phJ.Phys.G(2018)·6 citations
16. 16*

    NLO QCD+EW corrections to diphoton production in association with a vector boson

    Nicolas Greiner🇨🇭 · Marek Schönherr🇨🇭

    Processes with three external electroweak gauge boson allow for a measurement of triple and quartic gauge couplings. They can be used to constrain anomalous gauge couplings, where new physics might predominantly couple to electroweak gauge bosons. In this paper we chose a class of such processes where we consider two photons and an additional vector boson in the final state. As additional vector boson we consider either a third photon or a $W$ or $Z$ boson. For the latter two cases we assume a leptonic decay of the boson. We calculate the next-to-leading order QCD and electroweak corrections to these processes with a particular emphasis on the until now unknown electroweak corrections. We find that the electroweak corrections to the total cross section are moderate in the range of a few per cent at most, but can reach several tens of per cent in regions of phase space that are particularly interesting in the context of new physics searches. In addition we investigate the difference between additive and multiplicative scheme when combining QCD and electroweak corrections and we assess the importance of photon induced contributions to these processes.

    hep-phJHEP(2018)·30 citations
17. 17*

    Neutrino propagation in binary neutron star mergers in presence of nonstandard interactions

    Amélie Chatelain🇫🇷 · Maria Cristina Volpe🇫🇷

    We explore the impact of nonstandard interactions on neutrino propagation in accretion disks around binary neutron star mergers remnants. We show flavor evolution can be significantly modified even for values of the nonstandard couplings well below current bounds. We demonstrate the occurrence of I resonances as synchronized MSW phenomena and show that intricate conversion patterns might appear depending on the nonstandard interaction parameters. We discuss the possible implications for nucleosynthesis.

    hep-phnucl-thPRD(2018)·13 citations
18. 18*

    Triple parton scattering effects in $D$-meson production at the LHC

    Rafal Maciula🇵🇱 · Antoni Szczurek🇵🇱

    We study triple-parton scattering effects in open charm production in proton-proton collisions at the LHC. Predictions for one, two and three $c\bar{c}$ pairs production are given for $\sqrt{s}=7$ TeV and $\sqrt{s}=13$ TeV. Quite large cross sections, of the order of milibarns, for the triple-parton scattering mechanism are obtained. We suggest a measurement of three $D^0$ or three $\overline{D^0}$ mesons by the LHCb collaboration. The predicted visible cross sections are of the order of a few nanobarns. The counting rates including $D^0\to K^{-}{\pi }^{+}$ branching fractions are also given. We predict that at $\sqrt{s}=13$ TeV a few thousands of events of triple-$D^0$ production can be observed by the LHCb collaboration.

    hep-ph4 citations
19. 19*

    Associated production of $D$-mesons with jets at the LHC

    Rafal Maciula🇵🇱 · Antoni Szczurek🇵🇱

    We present several differential distributions for the associated production of charm and dijets. Both single-parton scattering (SPS) and double-parton scattering (DPS) contributions are calculated in the $k_T$-factorization approach. We have found regions of the phase space where the SPS contribution is negligible compared to the DPS one. The distribution in transverse momentum of charmed mesons as well as azimuthal correlations ($D^0\text{-jet}$, $D^0\overline{D^0}$) can be used for experimental identification of the DPS effects.

    hep-ph0 citations
20. 20*

    Leptogenesis as an origin of dark matter and baryon asymmetries in the E6 inspired SUSY models

    R. Nevzorov🇷🇺

    We explore leptogenesis within the E6 inspired U(1) extension of the MSSM in which exact custodial symmetry forbids tree-level flavour-changing transitions and the most dangerous baryon and lepton number violating operators. This supersymmetric (SUSY) model involves extra exotic matter beyond the MSSM. In the simplest phenomenologically viable scenarios the lightest exotic fermions are neutral and stable. These states should be substantially lighter than 1 eV forming hot dark matter in the Universe. The low-energy effective Lagrangian of the SUSY model under consideration possesses an approximate global U(1)_E symmetry associated with the exotic states. The U(1)_E symmetry is explicitly broken because of the interactions between the right-handed neutrino superfields and exotic matter supermultiplets. As a consequence the decays of the lightest right-handed neutrino/sneutrino give rise to both U(1)_E and U(1)_{B-L} asymmetries. When all right-handed neutrino/sneutrino are relatively light \sim 10^6-10^7 GeV the appropriate amount of the baryon asymmetry can be induced via these decays if the Yukawa couplings of the lightest right-handed neutrino superfields to the exotic matter supermultiplets vary between 10^{-4}-10^{-3}.

    hep-phPLB(2018)·14 citations
21. 21*

    Probing Baryogenesis through the Higgs Self-Coupling

    Manuel Reichert🇩🇪 · Astrid Eichhorn🇩🇪 · Holger Gies🇩🇪 · Jan M. Pawlowski🇩🇪 · Tilman Plehn🇩🇪 · Michael M. Scherer🇩🇪

    The link between a modified Higgs self-coupling and the strong first-order phase transition necessary for baryogenesis is well explored for polynomial extensions of the Higgs potential. We broaden this argument beyond leading polynomial expansions of the Higgs potential to higher polynomial terms and to non-polynomial Higgs potentials. For our quantitative analysis we resort to the functional renormalization group, which allows us to evolve the full Higgs potential to higher scales and finite temperature. In all cases we find that a strong first-order phase transition manifests itself in an enhancement of the Higgs self-coupling by at least 50%, implying that such modified Higgs potentials should be accessible at the LHC.

    hep-phhep-thPRD(2018)·81 citations
22. 22*

    Exclusive diffractive production of hadrons in $pp$ collisions

    Piotr Lebiedowicz🇵🇱 · Otto Nachtmann🇩🇪 · Antoni Szczurek🇵🇱

    We discuss central exclusive diffractive dihadron production in proton-proton collisions at high energies. The calculation is based on a tensor pomeron model and the amplitudes for the processes are formulated in an effective field-theoretic approach. We include a purely diffractive dipion continuum, and the scalar and tensor resonances decaying into the ${\pi }^{+}{\pi }^{-}$ pairs as well as the photoproduction contributions (${\rho }^0$, Drell-Söding). We discuss how two pomerons couple to tensor meson $f_2(1270)$ and the interference effects of the scalar and tensor resonances and the dipion continuum. The theoretical results are compared with existing CDF and CMS experimental data. We discuss also the Drell-Hiida-Deck type mechanism with centrally produced ${\rho }^0$ meson associated with a very forward/backward $\pi N$ system. For the $pp\to pp{\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ reaction we consider both the $\sigma \sigma$ and $\rho \rho$ contributions as well as the triple Regge exchange mechanism. Predictions for planned or being carried out experiments (STAR, ALICE, ATLAS, CMS) are presented. We show the influence of the experimental cuts on the integrated cross section and on various differential distributions for outgoing particles.

    hep-ph0 citations
23. 23*

    Inclusive production of vector quarkonia at the LHC

    Anna Cisek🇵🇱 · Antoni Szczurek🇵🇱

    We discuss prompt production of $J/\psi$ mesons in proton-proton collisions at the LHC within NRQCD k$t$-factorization approach using Kimber-Martin-Ryskin (KMR) and Kutak-Stasto (KS) unintegrated gluon distribution (UGDF). We include both direct color-singlet production $gg\to J/\psi g$ as well as a feed-down from ${\chi }_c\to J/\psi \gamma$ and ${\psi }^{\prime }\to J/\psi X$. The corresponding matrix elements for $gg\to J/\psi$, $gg\to {\psi }^{\prime }$ and $gg\to {\chi }_c$ include parameters of the nonrelativistic space wave functions of the quarkonia at $r=0$, which are taken from potential models from the literature. We calculate the ratio of the corresponding cross sections for ${\chi }_{c2}/{\chi }_{c1}$. We compare our results with ATLAS experimental data. Differential distributions in rapidity and transverse momentum of $J/\psi$ and ${\psi }^{\prime }$ are calculated and compared to experimental data of the ALICE and LHCb collaborations. We present results for three different values of energy 2.76 TeV, 7 TeV and 13 TeV.

    hep-ph1 citation
24. 24*

    Precise predictions for electroweakino-pair production in association with a jet at the LHC

    Julien Baglio🇩🇪 · Barbara Jäger🇩🇪 · Matthias Kesenheimer🇩🇪

    We present the full NLO SUSY-QCD corrections to the pair production of neutralinos and charginos at the LHC in association with a jet and their matching to parton-shower programs in the framework of the POWHEG-BOX package. The code we have developed provides a SUSY Les Houches Accord interface for setting electroweak and supersymmetric input parameters. Decays of the neutralinos and charginos and parton-shower effects can be simulated with multi-purpose programs such as PYTHIA. The capabilities of the code are illustrated by phenomenological results for a parameter point in the framework of pMSSM10, compatible with present experimental limits on supersymmetry. We find that NLO-QCD corrections as well as parton-shower effects are of primary importance for the appropriate description of jet distributions.

    hep-phhep-exJHEP(2018)·6 citations
25. 25*

    Progress in high-energy cosmic ray physics

    Silvia Mollerach🇦🇷 · Esteban Roulet🇦🇷

    We review some of the recent progress in our knowledge about high-energy cosmic rays, with an emphasis on the interpretation of the different observational results. We discuss the effects that are relevant to shape the cosmic ray spectrum and the explanations proposed to account for its features and for the observed changes in composition. The physics of air-showers is summarized and we also present the results obtained on the proton-air cross section and on the muon content of the showers. We discuss the cosmic ray propagation through magnetic fields, the effects of diffusion and of magnetic lensing, the cosmic ray interactions with background radiation fields and the production of secondary neutrinos and photons. We also consider the cosmic ray anisotropies, both at large and small angular scales, presenting the results obtained from the TeV up to the highest energies and discuss the models proposed to explain their origin.

    ↳ astro-ph.HEhep-phPPNP(2018)·65 citations
26. 26*

    Strong-isospin-breaking correction to the muon anomalous magnetic moment from lattice QCD at the physical point

    Bipasha Chakraborty🇺🇸 · C. T. H. Davies🇬🇧 · C. DeTar🇺🇸 · A. X. El-Khadra🇺🇸 · E. Gámiz🇪🇸 · Steven Gottlieb🇺🇸 · D. Hatton🇬🇧 · J. Koponen🇮🇹 · A. S. Kronfeld🇺🇸 · J. Laiho🇺🇸 · G. P. Lepage🇺🇸 · Yuzhi Liu🇺🇸 and 8 other authors

    All lattice-QCD calculations of the hadronic-vacuum-polarization contribution to the muon's anomalous magnetic moment to-date have been performed with degenerate up- and down-quark masses. Here we calculate directly the strong-isospin-breaking correction to $a_{\mu }^{\mathrm{HVP}}$ for the first time with physical values of $m_u$ and $m_d$ and dynamical $u$, $d$, $s$, and $c$ quarks, thereby removing this important source of systematic uncertainty. We obtain a relative shift to be applied to lattice-QCD results obtained with degenerate light-quark masses of $\delta a_{\mu }^{\mathrm{HVP},m_u\ne m_d}$= +1.5(7)%, in agreement with estimates from phenomenology and a recent lattice-QCD calculation with unphysically heavy pions.

    ↳ hep-lathep-phPRL(2018)·139 citations
27. 27*

    Heavy quarkonia in a contact interaction and an algebraic model: mass spectrum, decay constants, charge radii and elastic and transition form factors

    K. Raya🇲🇽 · M.A. Bedolla🇮🇹 · J.J. Cobos-Martínez🇲🇽 · A. Bashir🇲🇽

    For the flavor-singlet heavy quark system of bottomonia, we compute the masses of the ground state mesons in four different channels, namely, pseudo-scalar (${\eta }_b(1S)$), vector (${\rm Y}(1S)$), scalar (${\chi }_{b_0}(1P)$) and axial vector (${\chi }_{b_1}(1P)$). We also calculate the weak decay constants of the ${\eta }_b(1S)$ and ${\rm Y}(1S)$ as well as the charge radius of ${\eta }_b(1S)$. It complements our previous study of the corresponding charmonia systems: ${\eta }_c(1S)$, $J/\Psi (1S)$, ${\chi }_{c_0}(1P)$) and (${\chi }_{c_1}(1P)$). The unified formalism for this analysis is provided by a symmetry-preserving Schwinger-Dyson equations treatment of a vector$\times$vector contact interaction. Whenever a comparison is possible, our results are in fairly good agreement with experimental data and model calculations based upon Schwinger-Dyson and Bethe-Salpeter equations involving sophisticated interaction kernels. Within the same framework, we also report the elastic and transition form factors to two photons for the pseudo-scalar channels ${\eta }_c(1S)$ and ${\eta }_b(1S)$ in addition to the elastic form factors for the vector mesons $J/\Psi$ and ${\rm Y}$ for a wide range of photon momentum transfer squared ($Q^2$). For ${\eta }_c(1S)$ and ${\eta }_b(1S)$, we also provide predictions of an algebraic model which correlates remarkably well between the known infrared and ultraviolet limits of these form factors.

    ↳ nucl-thhep-phFew Body Syst.(2018)·50 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.