Thu·May 11, 2017Thursday·May 11, 2017

1. 01*

   Baikov-Lee Representations Of Cut Feynman Integrals

   Mark Harley🇮🇪 · Francesco Moriello🇨🇭 · Robert M. Schabinger🇮🇪

   We develop a general framework for the evaluation of $d$-dimensional cut Feynman integrals based on the Baikov-Lee representation of purely-virtual Feynman integrals. We implement the generalized Cutkosky cutting rule using Cauchy's residue theorem and identify a set of constraints which determine the integration domain. The method applies equally well to Feynman integrals with a unitarity cut in a single kinematic channel and to maximally-cut Feynman integrals. Our cut Baikov-Lee representation reproduces the expected relation between cuts and discontinuities in a given kinematic channel and furthermore makes the dependence on the kinematic variables manifest from the beginning. By combining the Baikov-Lee representation of maximally-cut Feynman integrals and the properties of periods of algebraic curves, we are able to obtain complete solution sets for the homogeneous differential equations satisfied by Feynman integrals which go beyond multiple polylogarithms. We apply our formalism to the direct evaluation of a number of interesting cut Feynman integrals.

   hep-phJHEP(2017)·93 citations
2. 02*

   Fate of in-medium heavy quarks via a Lindblad equation

   Davide De Boni🇬🇧

   What is the dynamics of heavy quarks and antiquarks in a quark gluon plasma? Can heavy-quark bound states dissociate? Can they (re)combine? These questions are addressed by investigating a Lindblad equation that describes the quantum dynamics of the heavy quarks in a medium. The Lindblad equations for a heavy quark and a heavy quark-antiquark pair are derived from the gauge theory, following a chain of well-defined approximations. In this work the case of an abelian plasma has been considered, but the extension to the non-abelian case is feasible. A one-dimensional simulation of the Lindblad equation is performed to extract information about bound-state dissociation, recombination and quantum decoherence for a heavy quark-antiquark pair. All these phenomena are found to depend strongly on the imaginary part of the inter-quark potential.

   hep-phnucl-thJHEP(2017)·43 citations
3. 03*

   Visible neutrino decay at DUNE

   Pilar Coloma🇺🇸 · Orlando L. G. Peres🇧🇷

   If the heaviest neutrino mass eigenstate is unstable, its decay modes could include lighter neutrino eigenstates. In this case part of the decay products could be visible, as they would interact at neutrino detectors via mixing. At neutrino oscillation experiments, a characteristic signature of such \emph{visible neutrino decay} would be an apparent excess of events at low energies. We focus on a simple phenomenological model in which the heaviest neutrino decays as ${\nu }_3\to {\nu }_{1,2}+\varphi$, where $\varphi$ is a new light scalar. If neutrinos are Majorana particles the helicity-flipping decays would be observable (i.e., $\nu \to \bar{\nu }+\varphi$), leading to interesting observable consequences on the event rates. We compute the sensitivities of the Deep Underground Neutrino Experiment (DUNE) to the couplings of the new scalar as a function of the lightest neutrino mass. Under the assumption that only the heaviest neutrino is unstable, and for a normal mass ordering, we find that DUNE will be sensitive to values of ${\tau }_3/m_3>1.95-2.6\times 10^{-10}$~s/eV (90\% C.L.) (depending on the lightest neutrino mass), where ${\tau }_3$ and $m_3$ are the lifetime and mass of ${\nu }_3$, respectively.

   hep-phhep-ex53 citations
4. 04*

   Scalar one-loop four-point Feynman integrals with complex internal masses

   K. H. Phan🇻🇳

   Based on the method in Refs.~{\tt [D.~Kreimer, Z.\ Phys.\ C {\bf 54} (1992) 667} and {\tt Int.\ J.\ Mod.\ Phys.\ A {\bf 8} (1993) 1797]}, we present analytic results for scalar one-loop four-point Feynman integrals with complex internal masses. The results are not only valid for complex internal masses, but also for real internal mass cases. Different from the traditional approach proposed by G. 't Hooft and M. Veltman in the paper {\tt[Nucl.\ Phys.\ B {\bf 153} (1979) 365]}, this method can be extended to evaluate tensor integrals directly. Therefore, it may open a new approach to cure the inverse Gram determinant problem analytically. We then implement the results into a computer package which is {\tt ONELOOP4PT.CPP}. In numerical checks, one compares the program to {\tt LoopTools version} $2.12$ in both real and complex mass cases. We find a perfect agreement between the results generated from this work and {\tt LoopTools}.

   hep-phPTEP(2017)·2 citations
5. 05*

   Testing B-violating signatures from Exotic Instantons in future colliders

   Andrea Addazi🇮🇹 · Xian-Wei Kang🇹🇼 · Maxim Yu. Khlopov🇷🇺

   We discuss possible implications of Exotic Stringy instantons for Baryon-violating signatures in future colliders. In particular, we discuss high-energy quarks collisions and $\Lambda -\bar{\Lambda }$ transitions. In principle, $\Lambda -\bar{\Lambda }$ process can be probed by high-luminosity electron-positron colliders. However, we find that an extremely high luminosity is needed in order to provide a (somewhat) stringent bound compared to the current data on $NN\to \pi \pi ,KK$. On the other hand, (exotic) instanton-induced six quark interactions can be tested in near future high-energy colliders beyond LHC, at energies around $20-100\mathrm{TeV}$. Super proton-proton collider (SppC) is capable of such measurement given the proposed energy level of 50-90 TeV. Comparison with other channels is made. In particular, we show the compatibility of our model with neutron-antineutron and $NN\to \pi \pi ,KK$ bounds.

   hep-phCPC(2017)·3 citations
6. 06*

   Reopen parameter regions in Two-Higgs Doublet Models

   Florian Staub🇩🇪

   The stability of the electroweak potential is a very important constraint for models of new physics. At the moment, it is standard for Two-Higgs doublet models (THDM), singlet or triplet extensions of the standard model to perform these checks at tree-level. However, these models are often studied in the presence of very large couplings. Therefore, it can be expected that radiative corrections to the potential are important. We study these effects at the example of the THDM type-II and find that loop corrections can revive more than 50% of the phenomenological viable points which are ruled out by the tree-level vacuum stability checks. Similar effects are expected for other extension of the standard model.

   hep-phhep-exPLB(2018)·34 citations
7. 07*

   Total ${\pi }^{+}p$ cross section extracted from the leading neutron spectra at the LHC

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

   We use the very forward neutron energy spectra measured by the Large Hadron Collider forward (LHCf) experiment at 7 TeV to extract the ${\pi }^{+}p$ total cross section at centre-of-mass energies in the range 2.3$-$3.5 TeV. To do this we have to first isolate the $\pi$-exchange pole in forward neutron production in $pp$ collisions, by evaluating other possible contributions. Namely, those from $\rho$ and $a_2$ exchange, from both eikonal and enhanced screening effects, from migration, from neutron production by $\Delta$-isobar decay and from diffractive nucleon excitations. We discuss the possible theoretical uncertainties due to the fact that the data do not exactly reach the $\pi$ pole. We choose the kinematical domain where the pion contribution dominates and demonstrate the role of the different corrections which could affect the final result.

   hep-phPRD(2017)·15 citations
8. 08*

   New Old Mechanism of Dark Matter Burning

   A.D. Dolgov🇷🇺

   Recently several papers have been published, where "a new mechanism" of dark matter burning and freezing is suggested. The usual two-body annihilation process is generalized to multi-body initial states, mostly three-body. These processes have quite a few interesting cosmological implications. I want to indicate here that such a process was studied in 1980 to determine the cosmological number density of the so called theta-particles. The file of the translated into English original paper and the reference to the published English version are attached.

   hep-phastro-ph.CO23 citations
9. 09*

   Phenomenology of a Neutrino-DM Coupling: The Scalar Case

   Celine Boehm🇬🇧 · Andres Olivares-Del Campo🇬🇧 · Sergio Palomares-Ruiz🇪🇸 · Silvia Pascoli🇬🇧

   Dark matter (DM) and neutrinos are the two most compelling pieces of evidence of new physics beyond the Standard Model of Particle Physics but these are often treated as belonging to two different sectors. Yet DM-neutrino interactions are known to have cosmological consequences. Here, we study the scenario of a scalar DM candidate coupled to left-handed neutrinos via a Dirac mediator. We determine the mass of a DM candidate that yields the right DM relic abundance in a thermal scenario and it is consistent with large-scale structure formation. In order to satisfy both constraints, a complex DM candidate should have a mass larger than $8.14$ keV while the mass of a real DM candidate should be above $18.1$ eV, independently of the value of the DM-neutrino coupling.

   hep-ph10 citations
10. 10*

    $\mu$-Hybrid Inflation with Low Reheat Temperature and Observable Gravity Waves

    Mansoor Ur Rehman🇵🇰 · Qaisar Shafi🇺🇸 · Fariha K. Vardag🇵🇰

    In $\mu$-hybrid inflation a nonzero inflaton vacuum expectation value induced by supersymmetry breaking is proportional to the gravitino mass $m_{3/2}$, which can be exploited to resolve the minimal supersymmetric standard model $\mu$ problem. We show how this scenario can be successfully implemented with $m_{3/2}\sim 1-100$ TeV and reheat temperature as low as $10^6$ GeV by employing a minimal renormalizable superpotential coupled with a well defined non-minimal Kähler potential. The tensor-to-scalar ratio $r$, a canonical measure of primordial gravity waves in most cases is less than or of the order of $10^{-6}-10^{-3}$.

    hep-phPRD(2017)·21 citations
11. 11*

    Triangle singularities in $B^{-}\to K^{-}{\pi }^{-}{D}_{s0}^{+}$ and $B^{-}\to K^{-}{\pi }^{-}{D}_{s1}^{+}$

    S. Sakai🇪🇸 · E. Oset🇪🇸 · A. Ramos🇪🇸

    We study the appearance of structures in the decay of the $B^{-}$ into $K^{-}{\pi }^{-}{D}_{s0}^{+}(2317)$ and $K^{-}{\pi }^{-}{D}_{s1}^{+}(2460)$ final states by forming invariant mass distributions of ${\pi }^{-}{D}_{s0}^{+}$ and ${\pi }^{-}{D}_{s1}^{+}$ pairs, respectively. The structure in the distribution is associated to the kinematical triangle singularity that appears when the $B^{-}\to K^{-}{K}^{\ast 0}{D}^0$ ($B^{-}\to K^{-}{K}^{\ast 0}{D}^{\ast 0}$) decay process is followed by the decay of the $K^{\ast 0}$ into ${\pi }^{-}{K}^{+}$ and the subsequent rescattering of the $K^{+}{D}^0$ ($K^{+}{D}^{\ast 0}$) pair forming the $D_{s0}^{+}(2317)$ ($D_{s1}^{+}(2460)$) resonance. We find this type of non-resonant peaks at 2850 MeV in the invariant mass of ${\pi }^{-}{D}_{s0}$ pairs from $B^{-}\to K^{-}{\pi }^{-}{D}_{s0}^{+}(2317)$ decays and around 3000 MeV in the invariant mass of ${\pi }^{-}{D}_{s1}^{+}$ pairs from $B^{-}\to K^{-}{\pi }^{-}{D}_{s1}^{+}(2460)$ decays. By employing the measured branching ratios of the $B^{-}\to K^{-}{K}^{\ast 0}{D}^0$ and $B^{-}\to K^{-}{K}^{\ast 0}{D}^{\ast 0}$ decays, we predict the branching ratios for the processes $B^{-}$ into $K^{-}{\pi }^{-}{D}_{s0}^{+}(2317)$ and $K^{-}{\pi }^{-}{D}_{s1}^{+}(2460)$, in the vicinity of the triangle singularity peak, to be about $8\times 10^{-6}$ and $1\times 10^{-6}$, respectively. The observation of this reaction would also give extra support to the molecular picture of the $D_{s0}^{+}(2317)$ and $D_{s1}^{+}(2460)$.

    hep-phnucl-thEPJA(2018)·49 citations
12. 12*

    Hillclimbing Higgs inflation

    Ryusuke Jinno🇰🇷 · Kunio Kaneta🇰🇷 · Kin-ya Oda🇯🇵

    We propose a realization of cosmic inflation with the Higgs field when the Higgs potential has degenerate vacua by employing the recently proposed idea of hillclimbing inflation. The resultant inflationary predictions exhibit a sizable deviation from those of the ordinary Higgs inflation.

    hep-phastro-ph.COgr-qchep-thPRD(2018)·29 citations
13. 13*

    Next-to-leading-order QCD and electroweak corrections to WWW production at proton-proton colliders

    Stefan Dittmaier🇩🇪 · Alexander Huss🇨🇭 · Gernot Knippen🇩🇪

    Triple-W-boson production in proton-proton collisions allows for a direct access to the triple and quartic gauge couplings and provides a window to the mechanism of electroweak symmetry breaking. It is an important process to test the Standard Model (SM) and might be background to physics beyond the SM. We present a calculation of the next-to-leading order (NLO) electroweak corrections to the production of WWW final states at proton-proton colliders with on-shell W bosons and combine the electroweak with the NLO QCD corrections. We study the impact of the corrections to the integrated cross sections and to kinematic distributions of the W bosons. The electroweak corrections are generically of the size of 5-10% for integrated cross sections and become more pronounced in specific phase-space regions. The real corrections induced by quark-photon scattering turn out to be as important as electroweak loops and photon bremsstrahlung corrections, but can be reduced by phase-space cuts. Considering that prior determinations of the photon parton distribution function (PDF) involve rather large uncertainties, we compare the results obtained with different photon PDFs and discuss the corresponding uncertainties in the NLO predictions. Moreover, we determine the scale and total PDF uncertainties at the LHC and a possible future 100 TeV pp collider.

    hep-phJHEP(2017)·38 citations
14. 14*

    $0^{+}$ tetraquark states from improved QCD sum rules: delving into $X(5568)$

    Jian-Rong Zhang🇨🇳 · Jing-Lan Zou🇨🇳 · Jin-Yun Wu🇨🇳

    In order to investigate the possibility of the recently observed $X(5568)$ being a $0^{+}$ tetraquark state, we make an improvement to the study of the related various configuration states in the framework of the QCD sum rules. Particularly, to ensure the quality of the analysis, condensates up to dimension $12$ are included to inspect the convergence of operator product expansion (OPE) and improve the final results of the studied states. We note that some condensate contributions could play an important role on the OPE side. By releasing the rigid OPE convergence criterion, we arrive at the numerical value $5.57_{-0.23}^{+0.35}\text{mbox}GeV$ for the scalar-scalar diquark-antidiquark $0^{+}$ state, which agrees with the experimental data for the $X(5568)$ and could support its interpretation in terms of a $0^{+}$ tetraquark state with the scalar-scalar configuration. The corresponding result for the axial-axial current is calculated to be $5.77_{-0.33}^{+0.44}\text{mbox}GeV$, which is still consistent with the mass of $X(5568)$ in view of the uncertainty. The feasibility of $X(5568)$ being a tetraquark state with the axial-axial configuration therefore cannot be definitely excluded. For the pseudoscalar-pseudoscalar and the vector-vector cases, their unsatisfactory OPE convergence make it difficult to find reasonable work windows to extract the hadronic information.

    hep-phhep-exCPC(2018)·18 citations
15. 15*

    Fully differential NLO predictions for the radiative decay of muons and taus

    G. M. Pruna🇨🇭 · A. Signer🇨🇭 · Y. Ulrich🇨🇭

    We present a general purpose Monte Carlo program for the calculation of the radiative muon decay $\mu \to e\nu \bar{\nu }\gamma$ and the radiative decays $\tau \to e\nu \bar{\nu }\gamma$ and $\tau \to \mu \nu \bar{\nu }\gamma$ at next-to-leading order in the Fermi theory. The full dependence on the lepton masses and polarization of the initial-sate lepton are kept. We study the branching ratios for these processes and show that fully-differential next-to-leading order corrections are important for addressing a tension between BaBar's recent measurement of the branching ratio $\mathcal{B}(\tau \to e\nu \bar{\nu }\gamma )$ and the Standard Model prediction. In addition, we study various distributions of the process $\mu \to e\nu \bar{\nu }\gamma$ and obtain precise predictions for the irreducible background to $\mu \to e\gamma$ searches, tailored to the geometry of the MEG detector.

    hep-phhep-exPLB(2017)·23 citations
16. 16*

    Heavy neutrino mixing in the T2HK, the T2HKK and an extension of the T2HK with a detector at Oki Islands

    Yugo Abe🇯🇵 · Yusuke Asano🇯🇵 · Naoyuki Haba🇯🇵 · Toshifumi Yamada🇯🇵

    We study the discovery potential for the mixing of heavy isospin-singlet neutrinos in extensions of the Tokai-to-Kamioka (T2K) experiment: The Tokai-to-Hyper-Kamiokande (T2HK), the Tokai-to-Hyper-Kamiokande-to-Korea (T2HKK), and a plan of adding a new detector at Oki Islands to the T2HK. We parametrize the mixing of heavy neutrinos in terms of a non-unitary mixing matrix acting on active flavors. It is shown that in the T2HK and T2HKK, the sensitivity to heavy neutrino mixing deteriorates for some values of $CP$-violating phases in the standard and the non-unitary mixing matrices, but the deterioration is drastically mitigated if a detector at Oki Islands is added to the T2HK. We also consider the feasibility of measuring the mass hierarchy and the standard $CP$-violating phase ${\delta }_{CP}$ in the presence of heavy neutrino mixing, by fitting experimental data with the standard oscillation parameters only, i.e., under the assumption of unitary mixing. It is revealed that such measurement can be performed to some accuracy in the T2HKK and the extension of the T2HK with a detector at Oki Islands, owing to the fact that data with largely varying $L/E$ are collected in these experiments, while it cannot be in the T2HK.

    hep-phEPJC(2017)·14 citations
17. 17*

    Relativistic model of Hamiltonian renormalization for bound states and scattering amplitudes

    Kamil Serafin (University of Warsaw)🇵🇱

    We test the renormalization group procedure for effective particles (RGPEP) on a model of fermion-scalar interaction based on the Yukawa theory. The model is obtained by truncating the Yukawa theory to just two Fock sectors in the Dirac front form of Hamiltonian dynamics, a fermion, and a fermion and a boson, for the purpose of simple analytic calculation that exhibits steps of the procedure.

    hep-phFew Body Syst.(2017)·3 citations
18. 18*

    Flavoured $B-L$ Local Symmetry and Anomalous Rare $B$ Decays

    Rodrigo Alonso🇨🇭 · Peter Cox🇯🇵 · Chengcheng Han🇯🇵 · Tsutomu T. Yanagida🇯🇵

    We consider a flavoured $B-L$ gauge symmetry under which only the third generation fermions are charged. Such a symmetry can survive at low energies (~TeV) while still allowing for two superheavy right-handed neutrinos, consistent with neutrino masses via see-saw and leptogenesis. We describe a mechanism for generating Yukawa couplings in this model and also discuss the low-energy phenomenology. Interestingly, the new gauge boson could explain the recent hints of lepton universality violation at LHCb, with a gauge coupling that remains perturbative up to the Planck scale. Finally, we discuss more general $U(1)$ symmetries and show that there exist only two classes of vectorial $U(1)$ that are both consistent with leptogenesis and remain phenomenologically viable at low-energies.

    hep-phPLB(2017)·117 citations
19. 19*

    Surprises from Complete Vector Portal Theories: New Insights into the Dark Sector and its Interplay with Higgs Physics

    Yanou Cui🇺🇸 · Francesco D'Eramo🇺🇸

    We study UV complete theories where the Standard Model (SM) gauge group is extended with a new abelian $U(1)$, and the field content is augmented by an arbitrary number of scalar and fermion SM singlets, potentially including dark matter (DM) candidates. Considerations such as classical and quantum gauge invariance of the full theory and S-matrix unitarity, not applicable within a simplified model approach, are shown to have significant phenomenological consequences. The lack of gauge anomalies leads to compact relations among the $U(1)$ fermion charges, and puts a lower bound on the number of dark fermions. Contrary to naive expectations, the DM annihilation to Zh is found to be p-wave suppressed, as hinted by perturbative unitarity of S-matrix, with dramatic implications for DM thermal relic density and indirect searches. Within this framework, the interplay between dark matter, new vector boson and Higgs physics is rather natural and generic.

    hep-phastro-ph.COhep-exhep-thPRD(2017)·39 citations
20. 20*

    Theory of Dark Matter

    Paul H. Frampton🇮🇹

    We discuss the hypothesis that the constituents of dark matter in the galactic halo are Primordial Intermediate-Mass Black Holes (PIMBHs). The status of axions and WIMPs is discussed, as are the methods for detecting PIMBHs with emphasis on microlensing. The role of the angular momentum J of the PIMBHs in their escaping previous detection is considered.

    hep-phastro-ph.GAgr-qchep-thMod.Phys.Lett.A(2017)·3 citations
21. 21*

    Lefschetz thimbles in fermionic effective models with repulsive vector-field

    Yuto Mori🇯🇵 · Kouji Kashiwa🇯🇵 · Akira Ohnishi🇯🇵

    We discuss two problems in complexified auxiliary fields in fermionic effective models, the auxiliary sign problem associated with the repulsive vector-field and the choice of the cut for the scalar field appearing from the logarithmic function. In the fermionic effective models with attractive scalar and repulsive vector-type interaction, the auxiliary scalar and vector fields appear in the path integral after the bosonization of fermion ilinears. When we make the path integral well-defined by the Wick rotation of the vector field, the oscillating Boltzmann weight appears in the partition function. This "auxiliary" sign problem can be solved by using the Lefschetz-thimble path-integral method, where the integration path is constructed in the complex plane. Another serious obstacle in the numerical construction of Lefschetz thimbles is caused by singular points and cuts induced by multivalued functions of the complexified scalar field in the momentum integration. We propose a new prescription which fixes gradient flow trajectories on the same Riemann sheet in the flow evolution by performing the momentum integration in the complex domain.

    ↳ hep-lathep-phhep-thnucl-thPLB(2018)·27 citations
22. 22*

    Chiral Battery, scaling laws and magnetic fields

    Sampurn Anand🇮🇳 · Jitesh R. Bhatt🇮🇳 · Arun Kumar Pandey🇮🇳

    We study the generation and evolution of magnetic field in the presence of chiral imbalance and gravitational anomaly which gives an additional contribution to the vortical current. The contribution due to gravitational anomaly is proportional to $T^2$ which can generate a seed magnetic field irrespective of plasma being hirally charged or neutral. We estimate the order of magnitude of the magnetic field to be $10^{30}$~G at $T\sim 10^9$ GeV, with a typical length scale of the order of $10^{-18}$ cm, which is much smaller than the Hubble radius at that temperature ($10^{-8}$ cm). Moreover, such a system possesses scaling symmetry. We show that the $T^2$ term in the vorticity current along with scaling symmetry leads to more power transfer from lower to higher length scale as compared to only chiral anomaly without scaling symmetry.

    ↳ astro-ph.COhep-phphysics.plasm-phJCAP(2017)·18 citations
23. 23*

    Proton structure fluctuations: constraints from HERA and applications to p+A collisions

    Heikki Mäntysaari🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸 · Prithwish Tribedy🇺🇸

    We constrain proton structure fluctuations at small-$x$ by comparing with the HERA diffractive vector meson production data, and find that large geometric fluctuations in the proton wave function are needed. Hydrodynamical simulations of proton-nucleus collisions including the fluctuating proton structure are found to be compatible with the momentum anisotropies measured at the LHC.

    ↳ nucl-thhep-phNPA(2017)·4 citations
24. 24*

    Generation of gravitational waves from symmetry restoration during inflation

    Cody Goolsby-Cole🇺🇸 · Lorenzo Sorbo🇺🇸

    We discuss the possibility of a feature in the spectrum of inflationary gravitational waves sourced by a scalar field $\chi$ whose vacuum fluctuations are amplified by a rapidly time dependent mass. Unlike previous work which has focused on the case in which the mass of the field $\chi$ vanishes only for an instant before becoming massive again, we study a system where the scalar field becomes and remains massless through the end of inflation as the consequence of the restoration of a shift symmetry. After applying appropriate constraints to our parameters, we find, for future CMB experiments, a small contribution to the tensor-to-scalar ratio which can be at most of the order $r\sim 10^{-5}$. At smaller scales probed by gravitational interferometers, on the other hand, the energy density in the gravitational waves produced this way might be above the projected sensitivity of LISA, ${\Omega }_{GW}{h}^2\sim 10^{-13}$, in a narrow region of parameter space. If there is more than one $\chi$ species, then these amplitudes are enhanced by a factor equal to the number of those species.

    ↳ astro-ph.COhep-phhep-thJCAP(2017)·13 citations
25. 25*

    Dependence of the propagators on the sampling of Gribov copies inside the first Gribov region of Landau gauge

    Axel Maas🇦🇹

    Beyond perturbation theory the number of gauge copies drastically increases due to the Gribov-Singer ambiguity. Any way of treating them defines, in principle, a new, non-perturbative gauge, and the gauge-dependent correlation functions can vary between them. Herein various such gauges will be constructed as completions of the Landau gauge inside the first Gribov region. The dependence of the propagators and the running coupling on these gauges will be studied for SU(2) Yang-Mills theory in two, three, and four dimensions using lattice gauge theory, and for a wide range of lattice parameters. While the gluon propagator is rather insensitive to the choice, the ghost propagator and the running coupling show a stronger dependence. It is also found that the influence of lattice artifacts is larger than in minimal Landau gauge.

    ↳ hep-lathep-phAnnals Phys.(2017)·20 citations
26. 26*

    Agravity up to infinite energy

    Alberto Salvio🇨🇭 · Alessandro Strumia🇨🇭

    The self-interactions of the conformal mode of the graviton are controlled, in dimensionless gravity theories (agravity), by a coupling $f_0$ that is not asymptotically free. We show that, nevertheless, agravity can be a complete theory valid up to infinite energy. When $f_0$ grows to large values, the conformal mode of the graviton decouples from the rest of the theory and does not hit any Landau pole provided that scalars are asymptotically conformally coupled and all other couplings approach fixed points. Then, agravity can flow to conformal gravity at infinite energy. We identify scenarios where the Higgs mass does not receive unnaturally large physical corrections. We also show a useful equivalence between agravity and conformal gravity plus two extra conformally coupled scalars, and give a simpler form for the renormalization group equations of dimensionless couplings as well as of massive parameters in the presence of the most general matter sector.

    ↳ hep-thgr-qchep-phEPJC(2018)·144 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.