Tue·Feb 6, 2018Tuesday·February 6, 2018

1. 01*

   Review: Long-baseline oscillation experiments as a tool to probe High Energy Models

   Pedro Pasquini🇧🇷

   We review the current status of neutrino oscillation experiments, mainly focussed on T2(H)K, NO$\nu$A and DUNE. Their capability to probe high energy physics is found in the precision measurement of the CP phase and ${\theta }_{23}$. In general, neutrino mass models predicts correlations among the mixing angles that can be used to scan and shrink down its parameter space. We updated previous analysis and presents a list of models that contain such structure.

   hep-phAdv.High Energy Phys.(2018)·12 citations
2. 02*

   iHixs 2 - Inclusive Higgs Cross Sections

   Falko Dulat🇺🇸 · Achilleas Lazopoulos🇨🇭 · Bernhard Mistlberger🇨🇭

   We present a new release of the program iHixs. This easy-to-use tool allows to derive state of the art predictions for the inclusive production cross section of a Higgs boson at hadron colliders in the gluon fusion production mode. This includes the most up-to-date corrections in perturbative QCD and electro-weak theory, effects due to finite quark masses as well as an option to perform threshold resummation. In particular, exact perturbative QCD corrections through N3LO are included in the heavy top quark effective theory. Furthermore, iHixs contains automatic routines that allow to assess residual uncertainties on the prediction for the Higgs boson production cross section according to well established standard definitions. iHixs can be obtained from https://github.com/dulatf/ihixs .

   hep-phhep-exComput.Phys.Commun.(2018)·162 citations
3. 03*

   Higgs Boson Production at Hadron Colliders at N3LO in QCD

   Bernhard Mistlberger🇨🇭

   We present the Higgs boson production cross section at Hadron colliders in the gluon fusion production mode through N3LO in perturbative QCD. Specifically, we work in an effective theory where the top quark is assumed to be infinitely heavy and all other quarks are considered to be massless. Our result is the first exact formula for a partonic hadron collider cross section at N3LO in perturbative QCD. Furthermore, this result represents the first analytic computation of a hadron collider cross section involving elliptic integrals. We derive numerical predictions for the Higgs boson cross section at the LHC. Previously this result was approximated by an expansion of the cross section around the production threshold of the Higgs boson and we compare our findings. Finally, we study the impact of our new result on the state of the art prediction for the Higgs boson cross section at the LHC.

   hep-phhep-thJHEP(2018)·292 citations
4. 04*

   Right-Handed Neutrinos: DM and LFV $vs$ Collider

   Meziane Chekkal🇩🇿 · Amine Ahriche🇩🇿 · Amine Bouziane Hammou🇩🇿 · Salah Nasri🇦🇪

   In a class of neutrino mass models with a lepton flavor violation (LFV) Yukawa interaction term that involves a heavy right handed neutrino, a charged scalar and a charged lepton, we investigate at the ILC@500 GeV the possibility of observing news physics. These models can address neutrino mass and dark matter without being in conflict with different LFV constraints. By imposing DM relic density and LFV constraints, we recast the analysis done by L3 collaboration at LEP-II of monophoton searches on our space parameter and look for new physics in such channels like monophoton and $SS(\gamma )$, where we give different cuts and show the predicted distributions. We show also that using polarized beams could improve the statistical significance.

   hep-phhep-exNuovo Cim.C(2018)·0 citations
5. 05*

   Type II Seesaw and tau lepton at the HL-LHC, HE-LHC and FCC-hh

   Tong Li🇦🇺

   The tau lepton plays important role in distinguishing neutrino mass patterns and determining the chirality nature in heavy scalar mediated neutrino mass models, in the light of the neutrino oscillation experiments and its polarization measurement. We investigate the lepton flavor signatures with tau lepton at LHC upgrades, i.e. HL-LHC, HE-LHC and FCC-hh, through leptonic processes from doubly charged Higgs in the Type II Seesaw. We find that for the channel with one tau lepton in final states, the accessible doubly charged Higgs mass at HL-LHC can reach 655 GeV and 695 GeV for the neutrino mass patterns of normal hierarchy (NH) and inverted hierarchy (IH) respectively, with the luminosity of 3000 fb${}^{-1}$. Higher masses, 975-1930 GeV for NH and 1035-2070 GeV for IH, can be achieved at HE-LHC and FCC-hh.

   hep-phJHEP(2018)·27 citations
6. 06*

   Recursive model for the fragmentation of polarized quarks

   A. Kerbizi🇮🇹 · X. Artru🇫🇷 · Z. Belghobsi🇩🇿 · F. Bradamante🇮🇹 · A. Martin🇮🇹

   We present a model for Monte Carlo simulation of the fragmentation of a polarized quark. The model is based on string dynamics and the ${}^3{P}_0$ mechanism of quark pair creation at string breaking. The fragmentation is treated as a recursive process, where the splitting function of the subprocess $q\to h+q^{\prime }$ depends on the spin density matrix of the quark $q$. The ${}^3{P}_0$ mechanism is parametrized by a complex mass parameter $\mu$, the imaginary part of which is responsible for single spin asymmetries. The model has been implemented in a Monte Carlo program to simulate jets made of pseudoscalar mesons. Results for single hadron and hadron pair transverse-spin asymmetries are found to be in agreement with experimental data from SIDIS and $e^{+}{e}^{-}$ annihilation. The model predictions on the jet-handedness are also discussed.

   hep-phPRD(2018)·32 citations
7. 07*

   Renormalization-Group Equations of Neutrino Masses and Flavor Mixing Parameters in Matter

   Zhi-zhong Xing🇨🇳 · Shun Zhou🇨🇳 · Ye-Ling Zhou🇬🇧

   We borrow the general idea of renormalization-group equations (RGEs) to understand how neutrino masses and flavor mixing parameters evolve when neutrinos propagate in a medium, highlighting a meaningful possibility that the genuine flavor quantities in vacuum can be extrapolated from their matter-corrected counterparts to be measured in some realistic neutrino oscillation experiments. Taking the matter parameter $a\equiv 2\sqrt{2}{G}_{\mathrm{F}}^{}{N}_e^{}E$ to be an arbitrary scale-like variable with $N_e^{}$ being the net electron number density and $E$ being the neutrino beam energy, we derive a complete set of differential equations for the effective neutrino mixing matrix $V$ and the effective neutrino masses ${\tilde{m}}_i^{}$ (for $i=1,2,3$). Given the standard parametrization of $V$, the RGEs for $\{{\tilde{\theta }}_{12}^{},{\tilde{\theta }}_{13}^{},{\tilde{\theta }}_{23}^{},\tilde{\delta }\}$ in matter are formulated for the first time. We demonstrate some useful differential invariants which retain the same form from vacuum to matter, including the well-known Naumov and Toshev relations. The RGEs of the partial $\mu$-$\tau$ asymmetries, the off-diagonal asymmetries and the sides of unitarity triangles of $V$ are also obtained as a by-product.

   hep-phhep-exJHEP(2018)·25 citations
8. 08*

   The leptophilic dark matter in the Sun: the minimum testable mass

   Zheng-Liang Liang🇨🇳 · Yi-Lei Tang🇰🇷 · Zi-Qing Yang🇨🇳

   The physics of the solar dark matter (DM) that are captured and thermalise through the DM-nucleon interaction has been extensively studied. In this work, we consider the leptophilic DM scenario where the DM particles interact exclusively with the electrons through the axial-vector coupling. We investigate relevant phenomenologies in the Sun, including its capture, evaporation and thermalisation, and we calculate the equilibrium distribution using the Monte Carlo methods, rather than adopting a semi-analytic approximation. Based on the analysis, we then determine the minimum testable mass for which the DM-electron coupling strength can be probed via the neutrino observation. Compared to the case of the DM-nucleon interaction, it turns out that minimum detectable mass of the DM-electron interaction is roughly 1 GeV smaller, and a cross section about two orders of magnitude larger is required for the saturation of the annihilation signal.

   hep-phJCAP(2018)·9 citations
9. 09*

   Universal kinematic scaling as a probe of factorized long-distance effects in high-energy quarkonium production

   Pietro Faccioli🇵🇹 · Carlos Lourenco🇨🇭 · Mariana Araujo🇨🇭 · Joao Seixas🇵🇹

   Dimensional analysis reveals general kinematic scaling rules for the momentum, mass, and energy dependence of Drell-Yan and quarkonium cross sections. Their application to mid-rapidity LHC data provides strong experimental evidence supporting the validity of the factorization ansatz, a cornerstone of non-relativistic QCD, still lacking theoretical demonstration. Moreover, data-driven patterns emerge for the factorizable long-distance bound-state formation effects, including a remarkable correlation between the S-wave quarkonium cross sections and their binding energies. Assuming that this scaling can be extended to the P-wave case, we obtain precise predictions for the not yet measured feed-down fractions, thereby providing a complete picture of the charmonium and bottomonium feed-down structure. This is crucial information for quantitative interpretations of quarkonium production data, including studies of the suppression patterns measured in nucleus-nucleus collisions.

   hep-phEPJC(2018)·10 citations
10. 10*

    From identical S- and P-wave pT/M spectra to maximally distinct polarizations: probing NRQCD with chi states

    Pietro Faccioli🇵🇹 · Carlos Lourenco🇨🇭 · Mariana Araujo🇨🇭 · Joao Seixas🇵🇹 · Ilse Kratschmer🇦🇹 · Valentin Knunz🇨🇭

    A global analysis of ATLAS and CMS measurements reveals that, at mid-rapidity, the directly-produced ${\chi }_{c1}$, ${\chi }_{c2}$ and J/$\psi$ mesons have differential cross sections of seemingly identical shapes, when presented as a function of the mass-rescaled transverse momentum, $p_{\mathrm{T}}/M$. This identity of kinematic behaviours among S- and P-wave quarkonia is certainly not a natural expectation of non-relativistic QCD (NRQCD), where each quarkonium state is supposed to reflect a specific family of elementary production processes, of significantly different $p_{\mathrm{T}}$-differential cross sections. Remarkably, accurate kinematic cancellations among the variegated NRQCD terms (colour singlets and octets) of its factorization expansion can lead to a surprisingly good description of the data. This peculiar tuning of the NRQCD mixtures leads to a clear prediction regarding the ${\chi }_{c1}$ and ${\chi }_{c2}$ polarizations, the only observables not yet measured: they should be almost maximally different from one another, and from the J/$\psi$ polarization, a striking exception in the global panorama of quarkonium production. Measurements of the difference between the ${\chi }_{c1}$, ${\chi }_{c2}$ and J/$\psi$ polarizations, complementing the observed identity of momentum dependences, represent a decisive probe of NRQCD.

    hep-phEPJC(2018)·19 citations
11. 11*

    Calculation of Dissociation Temperature of Nucleon Using Gaussian Expansion Method

    Peng Cheng · Qi Meng · Qian Wu · Jialun Ping · Hongshi Zong

    The first study of the dissociation temperature of nucleon in hot QCD medium in the framework of constituent quark model is presented. The temperature-dependent potential energy of the three quark system, taking as the internal energy of the system are obtained from the free energy of the system, and the temperature-dependent free energy is derived based on Debye-Hückel theory. The lattice QCD results of the free energy for heavy three-quark system are employed and extended to the light three-quark system. The Schrödinger equation for nucleon is solved with the help of Gaussian expansion method and the dissociation temperature of the nucleon is determined according to the temperature dependence of binding energy and radii. Comparing with the dissociation temperature of $J/\psi$, the dissociation temperature of nucleon is higher. So, nucleon is more difficult to melt than Charmonium.

    hep-phPRD(2018)·8 citations
12. 12*

    The effect of Earth's gravitational field on the muon magic momentum

    Pawel Guzowski🇬🇧

    A recent set of articles considers the effect of Earth's gravity on the magnetic moments of fermions. The authors conclude that the gravitational effects cancel out for measurements of the electron anomalous magnetic moment, but for the muon measurements, given that they are performed on highly relativistic muons, the effect is large enough to explain the discrepancy between measured and theoretical values. In this paper this effect is shown to be too small given experimental resolutions, and has been absorbed into the systematic uncertainties of experiments performed to date. Future experiments will require muon momentum tuning at the keV/c level to see this effect.

    hep-ph5 citations
13. 13*

    Decays $A\to Z\gamma \gamma$ and $\varphi \to Z\gamma \gamma$ ($\varphi =h,H$) in two-Higgs doublet models

    R. Sánchez-Vélez🇲🇽 · G.Tavares-Velasco🇲🇽

    The one-loop contributions to the decays of the $CP$-odd and $CP$-even scalar bosons $A\to Z\gamma \gamma$ and $\varphi \to Z\gamma \gamma$ ($\varphi =h,H$) are calculated within the framework of $CP$-conserving THDMs, where they are induced by box and reducible Feynman diagrams. The behavior of the corresponding branching ratios are then analyzed within the type-II THDM in a region of the parameter space around the alignment limit and still consistent with experimental data. It is found that the $A\to Z\gamma \gamma$ branching ratio is only relevant when $m_A>m_H+m_Z$, but it is negligible otherwise. For $m_A>600$ GeV and $t_{\beta }\simeq O(1)$, $BR(A\to Z\gamma \gamma )$ can reach values of the order of $10^{-5}-10^{-4}$, but it decreases by about one order of magnitude as $t_{\beta }$ increases up to 10. A similar behavior is followed by the $H\to Z\gamma \gamma$ decay, which only has a non-negligible branching ratio when $m_H>m_A+m_Z$ and can reach the level of $10^{-4}-10^{-3}$ for $m_H>600$ GeV and $t_{\beta }\simeq O(1)$. We also estimated the branching ratios of these rare decays in the type-I THDM, where they can be about one order of magnitude larger than in type-II THDM. As far as the $h\to Z\gamma \gamma$ decay is concerned, since the properties of this scalar boson must be nearly identical to those of the SM Higgs boson, the $h\to Z\gamma \gamma$ branching ratio does not deviates significantly from the SM prediction, where it is negligibly small, of the order of $10^{-9}$. This result is in agreement with previous calculations.

    hep-phPRD(2018)·3 citations
14. 14*

    Strong Decays of the Orbitally Excited Scalar $D_0^{\ast }$ Mesons

    Xiao-Ze Tan🇨🇳 · Tianhong Wang🇨🇳 · Yue Jiang🇨🇳 · Si-Chen Li🇨🇳 · Qiang Li🇨🇳 · Guo-Li Wang🇨🇳 · Chao-Hsi Chang🇨🇳

    We calculate the two-body strong decays of the orbitally excited scalar mesons $D_0^{\ast }(2400)$ and $D_J^{\ast }(3000)$ by using the relativistic Bethe-Salpeter (BS) method. $D_J^{\ast }(3000)$ was observed recently by the LHCb Collaboration, the quantum number of which has not been determined yet. In this paper, we assume that it is the $0^{+}(2P)$ state and obtain the transition amplitude by using the PCAC relation, low-energy theorem and effective Lagrangian method. For the $1P$ state, the total widths of $D_0^{\ast }(2400{)}^0$ and $D_0^{\ast }(2400{)}^{+}$ are 226 MeV and 246 MeV, respectively. With the assumption of $0^{+}(2P)$ state, the widths of $D_J^{\ast }(3000{)}^0$ and $D_J^{\ast }(3000{)}^{+}$ are both about 131 MeV, which is close to the present experimental data. Therefore, $D_J^{\ast }(3000)$ is a strong candidate for the $2^3{P}_0$ state.

    hep-phEPJC(2018)·7 citations
15. 15*

    A mathematical solve on the three-interfering-resonances' parameters

    X.Han🇩🇪 · C. P. Shen🇨🇳

    The multiple-solution problem in determining the three-interfering-resonances' parameters from a fit to an experimentally measured distribution is considered in a mathematical viewpoint. In this paper it is shown that there are four numerical solutions for the fit with three coherent Breit-Wigner functions. Although the explicit analytical formulae can not be derived in this case, we provide some constraint equations between the four solutions. For the cases of nonrelativistic and relativistic Breit-Wigner forms of amplitude functions, numerical method is provided to derive the other solutions from the already obtained one based on the obtained constraint equations. In real experimental measurements with more complicated amplitude forms similar to Breit-Wigner functions, the same method can be deduced and performed to get numerical solutions. The well agreement between the solved solutions using this mathematical method and those from the fit directly verifies the correctness of the supplied constraint equations and mathematical methodology.

    hep-phhep-exCPC(2018)·5 citations
16. 16*

    First global next-to-leading order determination of diffractive parton distribution functions and their uncertainties within the {\tt xFitter} framework

    Muhammad Goharipour🇮🇷 · Hamzeh Khanpour🇮🇷 · Vadim Guzey🇷🇺

    We present {\tt GKG18-DPDFs}, a next-to-leading order (NLO) QCD analysis of diffractive parton distribution functions (diffractive PDFs) and their uncertainties. This is the first global set of diffractive PDFs determined within the {\tt xFitter} framework. This analysis is motivated by all available and most up-to-date data on inclusive diffractive deep inelastic scattering (diffractive DIS). Heavy quark contributions are considered within the framework of the Thorne-Roberts (TR) general mass variable flavor number scheme (GM-VFNS). We form a mutually consistent set of diffractive PDFs due to the inclusion of high-precision data from H1/ZEUS combined inclusive diffractive cross sections measurements. We study the impact of the H1/ZEUS combined data by producing a variety of determinations based on reduced data sets. We find that these data sets have a significant impact on the diffractive PDFs with some substantial reductions in uncertainties. The predictions based on the extracted diffractive PDFs are compared to the analyzed diffractive DIS data and with other determinations of the diffractive PDFs.

    hep-phhep-exEPJC(2018)·31 citations
17. 17*

    Strong Decay of $P_c(4380)$ Pentaquark in a Molecular Picture

    K. Azizi🇹🇷 · Y. Sarac🇹🇷 · H. Sundu🇹🇷

    There are different assumptions on the substructure of the pentaquarks $P_c(4380)$ and $P_c(4450)$, newly founded in $J/\psi N$ invariant mass by the LHCb collaboration, giving consistent mass results with the experimental observations. The experimental data and recent theoretical studies on their mass suggest interpretation of these states as spin-3/2 negative-parity and spin-5/2 positive-parity pentaquarks, respectively. There may exist opposite-parity states corresponding to these particles, as well. Despite a lot of studies, however, the nature and internal organization of these pentaquarks in terms of quarks and gluons are not clear. To this end we need more theoretical investigations on other physical properties of these states. In this accordance, we study a strong and dominant decay of the $P_c(4380)$ to $J/\psi$ and $N$ in the framework of three point QCD sum rule method. An interpolating current in a molecular form is applied to calculate six strong coupling form factors defining the transitions of the positive and negative parity spin-3/2 pentaquark states. The values of the coupling constants are used in the calculation of the decay widths of these transitions. The obtained results are compared with the existing experimental data.

    hep-phhep-exhep-latPLB(2018)·40 citations
18. 18*

    Soft photon and two hard jets forward production in proton-nucleus collisions

    Tolga Altinoluk🇵🇱 · Néstor Armesto🇪🇸 · Alex Kovner🇺🇸 · Michael Lublinsky🇮🇱 · Elena Petreska🇳🇱

    We calculate the cross section for production of a soft photon and two hard jets in the forward rapidity region in proton-nucleus collisions at high energies. The calculation is performed within the hybrid formalism. The hardness of the final particles is defined with respect to the saturation scale of the nucleus. We consider both the correlation limit of small momentum imbalance and the dilute target limit where the momentum imbalance is of the order of the hardness of the jets. The results depend on the first two transverse-momentum-dependent (TMD) gluon distributions of the nucleus.

    hep-phnucl-thJHEP(2018)·27 citations
19. 19*

    The Size Seems to Matter or Where Lies the "Asymptopia"?

    V. A. Petrov (A.A. Logunov Institute for High Energy Physics, NRC KI)🇷🇺 · V. A. Okorokov (National Research Nuclear University MEPhI)🇷🇺

    We discuss an apparent correlation between the onset of the rising regime for the total cross-sections and the slowdown of the rise of the forward slopes with energy. It is shown that even at highest energies achieved with the LHC the proper sizes of the colliding protons comprise the bulk of the the interaction region. This seems to witness that the "asymptopia" - a hypothetical "truly asymptotic" regime - lies at energies no less than $\mathcal{O}$(100 TeV). In the course of reasoning we also discuss the question of the dependence of the effective sizes of hadrons in collision on the type of their interaction.

    hep-phhep-exhep-thInt.J.Mod.Phys.A(2018)·25 citations
20. 20*

    Semi-inclusive production of two back-to-back hadron pairs in $e^{+}{e}^{-}$ annihilation revisited

    Hrayr H. Matevosyan🇦🇺 · Alessandro Bacchetta🇮🇹 · Daniël Boer🇳🇱 · Aurore Courtoy🇲🇽 · Aram Kotzinian🇦🇲 · Marco Radici🇮🇹 · Anthony W. Thomas🇦🇺

    The cross section for back-to-back hadron pair production in $e^{+}{e}^{-}$ annihilation provides access to the dihadron fragmentation functions (DiFF) needed to extract nucleon parton distribution functions from the semi-inclusive deep inelastic scattering (SIDIS) experiments with two detected final state hadrons. Particular attention is given to the so-called interference DiFF (IFF), which makes it possible to extract the transversity parton distribution of the nucleon in the collinear framework. However, previously unnoticed discrepancies were recently highlighted between the definitions of the IFFs appearing in the collinear kinematics when reconstructed from DiFFs entering the unintegrated fully differential cross sections of SIDIS and $e^{+}{e}^{-}$ annihilation processes. In this work, to clarify this problem we rederive the fully differential cross section for $e^{+}{e}^{-}$ annihilation at the leading-twist approximation. We find a mistake in the definition of the kinematics in the original expression that systematically affects a subset of terms and that leads to two significant consequences. First, the discrepancy between the IFF definitions in the cross sections for SIDIS and $e^{+}{e}^{-}$ annihilation is resolved. Second, the previously derived azimuthal asymmetry for accessing the helicity dependent DiFF $G_1^{\perp }$ in $e^{+}{e}^{-}$ annihilation vanishes, which explains the nonobservation of this asymmetry in the recent experimental searches by the $\mathtt{BELLE}$ Collaboration. We discuss the recently proposed alternative option to extract $G_1^{\perp }$.

    hep-phhep-exnucl-thPRD(2018)·33 citations
21. 21*

    Clockwork without supersymmetry

    Daniele Teresi🇧🇪

    The clockwork mechanism would be completely spoiled by the presence of a cosmological constant in the bulk of its 5D construction, or by analogous terms in the discrete case. It is believed that supersymmetry is required to forbid the appearance of these fatal terms, thus apparently tying the fate of the clockwork to the presence of supersymmetry. In this letter we argue that a robust clockwork can be obtained also without supersymmetry, by providing a model for the clockwork/linear dilaton EFT where this protection is instead related to diffeomorphism invariance in a higher number of extra dimensions. We show that the clockwork mechanism is a quite general setup that emerges, rather minimally, from pure gravity in the presence of $D-5$ additional flat extra dimensions. The linear dilaton model is obtained asymptotically in the limit of infinitely many extra dimensions. We then study the finite-$D$ theory, which is a deformation of the linear dilaton one, but still a clockwork theory for $D$ large enough.

    hep-phhep-thPLB(2018)·23 citations
22. 22*

    Unitarity issues in higher derivative field theories

    Manuel Asorey🇪🇸 · Lesław Rachwał🇧🇷 · Ilya Shapiro🇧🇷

    We analyze the unitarity properties of higher derivative quantum field theories which are free of ghosts and ultraviolet singularities. We point out that in spite of the absence of ghosts most of these theories are not unitary. This result confirms the difficulties of finding a consistent quantum field theory of quantum gravity.

    ↳ hep-thgr-qchep-phmath-ph+1Galaxies(2018)·33 citations
23. 23*

    Are there really conformal frames? Uniqueness of affine inflation

    Hemza Azri🇹🇷

    Here we concisely review the nonminimal coupling dynamics of a single scalar field in the context of purely affine gravity and extend the study to multifield dynamics. The coupling is performed via an affine connection and its associated curvature without referring to any metric tensor. The latter arises a posteriori and it may gain an emergent character like the scale of gravity. What is remarkable in affine gravity is the transition from nonminimal to minimal couplings which is realized by only field redefinition of the scalar fields. Consequently, the inflationary models gain a unique description in this context where the observed parameters, like the scalar tilt and the tensor-to-scalar ratio, are invariant under field reparametrization. Overall, gravity in its affine approach is expected to reveal interesting and rich phenomenology in cosmology and astroparticle physics.

    ↳ gr-qcastro-ph.HEhep-phhep-thInt.J.Mod.Phys.D(2018)·29 citations
24. 24*

    Instanton dominance over ${\alpha }_s$ at low momenta from lattice QCD simulations at $N_f=0$, $N_f=2+1$ and $N_f=2+1+1$

    Andreas Athenodorou🇨🇾 · Philippe Boucaud🇫🇷 · Feliciano de Soto🇪🇸 · José Rodríguez-Quintero🇪🇸 · Savvas Zafeiropoulos🇩🇪

    We report on an instanton-based analysis of the gluon Green functions in the Landau gauge for low momenta; in particular we use lattice results for ${\alpha }_s$ in the symmetric momentum subtraction scheme ($\mathrm{MOM}$) for large-volume lattice simulations. We have exploited quenched gauge field configurations, $N_f=0$, with both Wilson and tree-level Symanzik improved actions, and unquenched ones with $N_f=2+1$ and $N_f=2+1+1$ dynamical flavors (domain wall and twisted-mass fermions, respectively). We show that the dominance of instanton correlations on the low-momenta gluon Green functions can be applied to the determination of phenomenological parameters of the instanton liquid and, eventually, to a determination of the lattice spacing. We furthermore apply the Gradient Flow to remove short-distance fluctuations. The Gradient Flow gets rid of the QCD scale, ${\Lambda }_{\mathrm{QCD}}$, and reveals that the instanton prediction extents to large momenta. For those gauge field configurations free of quantum fluctuations, the direct study of topological charge density shows the appearance of large-scale lumps that can be identified as instantons, giving access to a direct study of the instanton density and size distribution that is compatible with those extracted from the analysis of the Green functions.

    ↳ hep-lathep-phEPJ Web Conf.(2018)·1 citation
25. 25*

    Renormalization, Conformal Ward Identities and the Origin of a Conformal Anomaly Pole

    Claudio Coriano🇮🇹 · Matteo Maria Maglio🇮🇹

    We investigate the emergence of a conformal anomaly pole in conformal field theories in the case of the $TJJ$ correlator. We show how it comes to be generated in dimensional renormalization, using a basis of 13 form factors (the $F$-basis), where only one of them requires renormalization $(F_{13})$, extending previous studies. We then combine recent results on the structure of the non-perturbative solutions of the conformal Ward identities (CWI's) for the $TJJ$ in momentum space, expressed in terms of a minimal set of 4 form factors ($A-$ basis), with the properties of the $F$-basis, and show how the singular behaviour of the corresponding form factors in both basis can be related. The result proves the centrality of such massless effective interactions induced by the anomaly, which have recently found realization in solid state, in the theory of topological insulators and of Weyl semimetals. This pattern is confirmed in massless abelian and nonabelian theories (QED and QCD) investigated at one-loop.

    ↳ hep-thcond-mat.str-elhep-phPLB(2018)·37 citations
26. 26*

    Nonlinear waves in magnetized quark matter and the reduced Ostrovsky equation

    D. A. Fogaça🇧🇷 · S. M. Sanches Jr.🇧🇷 · F. S. Navarra🇧🇷

    We study nonlinear waves in a nonrelativistic ideal and cold quark gluon plasma immersed in a strong uniform magnetic field. In the context of nonrelativistic hydrodynamics with an external magnetic field we derive a nonlinear wave equation for baryon density perturbations, which can be written as a reduced Ostrovsky equation. We find analytical solutions and identify the effects of the magnetic field.

    ↳ nucl-thhep-phCommun.Nonlinear Sci.Numer.Simul.(2019)·4 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.