Mon·Apr 8, 2019Monday·April 8, 2019

1. 01*

   NJL-type models in the presence of intense magnetic fields: the role of the regularization prescription

   Sidney S. Avancini🇧🇷 · Ricardo L. S. Farias🇧🇷 · Norberto N. Scoccola🇦🇷 · William R. Tavares🇧🇷

   We study the regularization dependence of the Nambu-Jona--Lasinio model (NJL) predictions for some properties of magnetized quark matter at zero temperature (and baryonic density) in the mean field approximation. The model parameter dependence for each regularization procedure is also analyzed in detail. We calculate the average and difference of the quark condensates using different regularization methods and compare with recent lattice results. In this context, the reliability of the different regularization procedures is discussed.

   hep-phhep-lathep-thnucl-thPRD(2019)·66 citations
2. 02*

   Solving the Gap Equation of the NJL Model through Iteration: Unexpected Chaos

   Angelo Martínez🇲🇽 · Alfredo Raya🇲🇽

   We explore the behavior of the iterative procedure to obtain the solution to the gap equation of the Nambu-Jona-Lasinio (NLJ) model for arbitrarily large values of the coupling constant and in the presence of a magnetic field and a thermal bath. We find that the iterative procedure shows a different behavior depending on the regularization scheme used. It is stable and very accurate when a hard cut-off is employed. Nevertheless, for the Paul-Villars and proper time regularization schemes, there exists a value of the coupling constant (different in each case) from where the procedure becomes chaotic and does not converge any longer.

   hep-phSymmetry(2019)·3 citations
3. 03*

   Sub-GeV Atmospheric Neutrinos and CP-Violation in DUNE

   Kevin J. Kelly🇺🇸 · Pedro A. N. Machado🇺🇸 · Ivan Martinez-Soler🇺🇸 · Stephen J. Parke🇺🇸 · Yuber F. Perez-Gonzalez🇺🇸

   We propose to use the unique event topology and reconstruction capabilities of liquid argon time projection chambers to study sub-GeV atmospheric neutrinos. The detection of low energy recoiled protons in DUNE allows for a determination of the leptonic $CP$-violating phase independent from the accelerator neutrino measurement. Our findings indicate that this analysis can exclude several values of ${\delta }_{CP}$ beyond the $3\sigma$ level. Moreover, the determination of the sub-GeV atmospheric neutrino flux will have important consequences in the detection of diffuse supernova neutrinos and in dark matter experiments.

   hep-phhep-exPRL(2019)·63 citations
4. 04*

   Non-equilibrium hydrodynamics of the quark-gluon plasma

   Mohammad Nopoush🇺🇸

   My dissertation is about the formulation and application of anisotropic hydrodynamics as a successful non-equilibrium hydrodynamics model for studying the QGP. For this purpose, I introduce the basic conformal anisotropic hydrodynamics formalism and then explain the ways we included realistic features (bulk degree of freedom, quasiparticle implementation of realistic equation of state, more realistic collisional kernel), to make it a suitable hydrodynamics model for studying the QGP generated in heavy-ion collisions. For verification of our model we have compared the evolution of model parameters predicted by aHydro and vHydro, with exact solution of the Boltzmann equation. However, the system is not conformal and the aHydro needed to be improved to include a realistic prescription for the equation of state which takes care of non-ideal effect in the dynamics. I have then designed a novel method for implementing the realistic equation of state (provided by lattice QCD) in the aHydro formalism. This model, called the quasiparticle aHydro model, integrates the non-conformal effects in the aHydro model. The non-conformal effects are due to strong interactions of plasma constituents which leads to temperature-dependence of the particles' effective mass in the system. Based on the quasiparticle picture, we have developed the quasiparticle aHydro (aHydroQP) model. We have then compared the phenomenological predictions of the aHydroQP model with experimental observations. Comparisons illustrate a high level of consistency between our model and the experimental data. Finally, I have calculated the quark self-energy in an anisotropic QGP. The quark self-energy is important because it encodes the way quarks gain interactional mass while in the hot QGP. I also have presented the calculation of gluon self-energy in hard loop approximation in an anisotropic QGP.

   hep-ph0 citations
5. 05*

   Lopsided texture compatible with thermal leptogenesis in partially composite Pati--Salam unification

   Masaki J. S. Yang🇯🇵

   In this paper, we consider a lopsided flavor texture compatible with thermal leptogenesis in partially composite Pati--Salam unification. The Davidson--Ibarra bound $M_{\nu R1}\gtrsim 10^9$ GeV for the successful thermal leptogenesis can be recast to the Froggatt--Nielsen (FN) charge of the lopsided texture. We found the FN charge $n_{\nu 1}$ of the lightest right-handed neutrino ${\nu }_{R1}$ can not be larger than a upper bound, $n_{\nu 1}\lesssim 4.5$. From the viewpoint of unification, the FN charges of the neutrinos $n_{\nu i}$ should be the same to that of other SM fermions. Then, two cases $n_{\nu i}=n_{qi}=(3,2,0)$ and $n_{\nu i}=n_{li}=(n+1,n,n)$ are considered. Observations of PS model shows that the case of $n=0$, $n_{li}=n_{di}=(1,0,0)$ will be the simplest realization. To decrease the FN charges of these fermions from the GUT invariant FN charges $n_{qi}=(3,2,0)$, we utilize the partial compositeness. In this picture, the hierarchies of Yukawa matrices are a consequence of mixings between massless chiral fermions $f_L,f_R^{\prime }$ and massive vector fermions $F_{L,R},F_{L,R}^{\prime }$. This is induced by the linear mixing terms ${\lambda }^f{\bar{f}}_L{F}_R$ and ${\lambda }^{f^{\prime }}{\bar{F}}_L^{\prime }{f}_R^{\prime }$. As a result of the partial compositeness, the decreases of FN charges require fine-tunings between mass and Yukawa matrices either for the increases of ${\lambda }^{f,f^{\prime }}$ or for the decreases of $M_{F,F^{\prime }}$. Therefore, the case for $n=2$ and $n_{di}=n_{li}=(3,2,2)$, which requires only increases of FN charges will be appropriate to build a natural model.

   hep-ph0 citations
6. 06*

   Centrality dependence of photon yield and elliptic flow from gluon fusion and splitting induced by magnetic fields in relativistic heavy-ion collisions

   Alejandro Ayala🇲🇽 · Jorge David Castaño-Yepes🇲🇽 · Isabel Dominguez Jimenez🇲🇽 · Jordi Salinas San Martín🇲🇽 · María Elena Tejeda-Yeomans🇲🇽

   We compute the photon yield and elliptic flow coefficient in relativistic heavy-ion collisions from gluon fusion and splitting processes induced by a magnetic field for different centralities. The calculation accounts for the intense magnetic field and the high gluon occupation number at early times. The photon production induced by these process represents an excess contribution over calculations without magnetic field effects. We compare this excess to the difference between PHENIX data and recent hydrodynamic calculations for the photon transverse momentum distribution and elliptic flow coefficient $v_2$. The time evolution of the field strength and reaction volume is computed using UrQMD. We show that with reasonable values for the saturation scale, the calculation helps to better describe the experimental results obtained at RHIC energies for the lowest part of the transverse photon momentum at different centralities.

   hep-phEPJA(2020)·29 citations
7. 07*

   Quark model description of $\psi (4260)$

   Roberto Bruschini🇪🇸 · Pedro González🇪🇸

   From lattice indications we follow a Born-Oppenheimer approximation to build a quark-antiquark static potential for $J^{PC}=1^{--}$ charmonium states below their first S- wave meson-meson threshold. We show that a good description of the mass and decay properties of the experimentally well established $\psi (4260)$ resonance is feasible.

   hep-phPRC(2019)·6 citations
8. 08*

   Complete treatment of single-photon emission in planar channeling

   Tobias N. Wistisen🇩🇪 · Antonino Di Piazza🇩🇪

   Approximate solutions of the Dirac equation are found for ultrarelativistic particles moving in a periodic potential, which depends only on one coordinate, transverse to the largest component of the momentum of the incoming particle. As an example we employ these solutions to calculate the radiation emission of positrons and electrons trapped in the planar potential found between the (110) planes in Silicon. This allows us to compare with the semi-classical method of Baier, Katkov and Strakhovenko, which includes the effect of spin and photon recoil, but neglects the quantization of the transverse motion. For high-energy electrons, the high-energy part of the angularly integrated photon energy spectrum calculated with the found wave functions differs from the corresponding one calculated with the semi-classical method. However, for lower particle energies it is found that the angularly integrated emission energy spectra obtained via the semi-classical method is in fairly good agreement with the full quantum calculation except that the positions of the harmonic peaks in photon energy and the photon emission angles are shifted.

   hep-phPRD(2019)·12 citations
9. 09*

   On coherent neutrino and antineutrino scattering off nuclei

   Vadim A. Bednyakov🇷🇺 · Dmitry V. Naumov🇷🇺

   Neutrino-nucleus $\nu A\to \nu A$ and antineutrino-nucleus $\bar{\nu }A\to \bar{\nu }A$ interactions, when the nucleus conserves its integrity, are discussed with coherent (elastic) and incoherent (inelastic) scattering regimes taken into account. In the first regime the nucleus remains in the same quantum state after the scattering and the cross-section depends on the quadratic number of nucleons. In the second regime the nucleus changes its quantum state and the cross-section has an essentially linear dependence on the number of nucleons. The coherent and incoherent cross-sections are driven by a nuclear nucleon form-factor squared $|F{|}^2$ term and a $(1-|F{|}^2)$ term, respectively. One has a smooth transition between the regimes of coherent and incoherent (anti)neutrino-nucleus scattering. Due to the neutral current nature these elastic and inelastic processes are indistinguishable if the nucleus recoil energy is only observed. One way to separate the coherent signal from the incoherent one is to register $\gamma$ quanta from deexcitation of the nucleus excited during the incoherent scattering. Another way is to use a very low-energy threshold detector and collect data at very low recoil energies, where the incoherent scattering is vanishingly small. In particular, for ${}^{133}\text{Cs}$ and neutrino energies of 30--50 MeV the incoherent cross-section is about 15-20\% of the coherent one. Therefore, the COHERENT experiment (with ${}^{133}\text{Cs}$) has measured the coherent elastic neutrino nucleus scattering (CE$\nu$NS) with the inelastic admixture at a level of 15-20\%, if the excitation $\gamma$ quantum escapes its detection.

   hep-phPhys.Part.Nucl.Lett.(2019)·13 citations
10. 10*

    Generating a Higgs Quartic

    Csaba Csáki🇺🇸 · Cong-sen Guan🇺🇸 · Teng Ma🇮🇱 · Jing Shu🇨🇳

    We present a simple mechanism for generating a Higgs quartic in composite Higgs models without a corresponding quadratic term. The extra quartic will originate from a Higgs dependent kinetic mixing between additional fermionic states. The mechanism can be naturally embedded to models with maximal symmetry as well as Twin Higgs models. The resulting Twin Higgs models will have a fully natural realistic Higgs potential, where the quartic mechanism will serve as the only source for the $Z_2$ breaking, while the top and gauge sectors can remain exactly $Z_2$ invariant.

    hep-phPRL(2020)·10 citations
11. 11*

    A quantum algorithm for high energy physics simulations

    Christian W. Bauer🇺🇸 · Wibe A. de Jong🇺🇸 · Benjamin Nachman🇺🇸 · Davide Provasoli🇺🇸

    Particles produced in high energy collisions that are charged under one of the fundamental forces will radiate proportionally to their charge, such as photon radiation from electrons in quantum electrodynamics. At sufficiently high energies, this radiation pattern is enhanced collinear to the initiating particle, resulting in a complex, many-body quantum system. Classical Markov Chain Monte Carlo simulation approaches work well to capture many of the salient features of the shower of radiation, but cannot capture all quantum effects. We show how quantum algorithms are well-suited for describing the quantum properties of final state radiation. In particular, we develop a polynomial time quantum final state shower that accurately models the effects of intermediate spin states similar to those present in high energy electroweak showers. The algorithm is explicitly demonstrated for a simplified quantum field theory on a quantum computer.

    hep-phquant-phPRL(2021)·159 citations
12. 12*

    SmeftFR -- Feynman rules generator for the Standard Model Effective Field Theory

    A. Dedes🇬🇷 · M. Paraskevas🇵🇱 · J. Rosiek🇵🇱 · K. Suxho🇬🇷 · L. Trifyllis🇬🇷

    We present SmeftFR, a Mathematica package designed to generate the Feynman rules for the Standard Model Effective Field Theory (SMEFT) including the complete set of gauge invariant operators up to dimension~6. Feynman rules are generated with the use of FeynRules package, directly in the physical (mass eigenstates) basis for all fields. The complete set of interaction vertices can be derived including all or any chosen subset of SMEFT operators. As an option, the user can also choose preferred gauge fixing, generating Feynman rules in unitary or $R_{\xi }$-gauges (the latter include generation of ghost vertices). Further options allow to treat neutrino fields as massless Weyl or massive Majorana fermions. The derived Lagrangian in the mass basis can be exported in various formats supported by FeynRules, such as UFO, FeynArts, etc. Initialisation of numerical values of $d=6$ Wilson coefficients used by SmeftFR is interfaced to WCxf format. The package also includes dedicated Latex generator allowing to print the result in clear human-readable form. SmeftFR can be downloaded from www.fuw.edu.pl/smeft.

    hep-phComput.Phys.Commun.(2020)·53 citations
13. 13*

    Brane cosmology and the self-tuning of the cosmological constant

    A. Amariti🇮🇹 · C. Charmousis🇫🇷 · D. Forcella🇫🇷 · E. Kiritsis🇬🇷 · F. Nitti🇫🇷

    The cosmology of branes undergoing the self-tuning mechanism of the cosmological constant is considered. The equations and matching conditions are derived in several coordinate systems, and an exploration of possible solution strategies is performed. The ensuing equations are solved analytically in the probe brane limit. We classify the distinct behavior for the brane cosmology and we correlate them with properties of the bulk (static) solutions. Their matching to the actual universe cosmology is addressed.

    ↳ hep-thgr-qchep-phJCAP(2019)·13 citations
14. 14*

    Discovery goals and opportunities in high energy physics: a defense of BSM-oriented exploration over signalism

    James D. Wells🇺🇸

    Discoveries come through exclusions, confirmations or revolutionary findings with respect to a theory canon populated by the Standard Model (SM) and beyond the SM (BSM) theories. Guaranteed discoveries are accomplished only through pursuit of BSM exclusion/confirmation, and thus require investment in the continual formation and analysis of a vibrant theory canon combined with investment in experiment with demonstrated capacity to make BSM exclusions/confirmations. Risks develop when steering away from BSM-oriented work toward its methodological rival, "signalism," which seeks to realize SM falsification or revolutionary discoveries outside the context of any BSM rationale. It is argued that such an approach leads to inscrutable exertions that reduce prospects for all discovery. The concepts are applied to the European Strategy Update, which seeks to identify future investments in forefront experiment that bring a balance of guaranteed and prospective value.

    ↳ physics.hist-phhep-exhep-ph2 citations
15. 15*

    Structure formation in dark energy cosmologies described by PADE parameterization

    Mehdi Rezaei🇮🇷

    We study the imprints on the formation of cosmic structures of a particular class of dark energy parameterizations dubbed PADE parameterization. Here we investigate how dark energy can affect the growth of large scale structures of the universe in framework of spherical collapse model. The dynamics of the spherical collapse of a dark matter halo depends on the properties of the dark energy model. We show that the properties of spherical collapse scenario are directly affected by the evolution of dark energy. We obtain the main parameters of spherical collapse for two different DE parameterizations in two different approaches: first the homogeneous DE approach, in which dark energy does not exhibit fluctuations on cluster scales and the other, clustered DE scenario in which, dark energy components inside the overdense region collapses similar to dark matter. Using the Sheth-Tormen mass function, we investigate the abundance of virialized halos in the framework of PADE parameterizations. Specifically, the present analysis shows that the number count of dark matter halos depends on the evolution of DE parameterizations and clustering properties of dark energy. Also we show that perturbations in phantom DE components enhance the growth of matter perturbations. This result were obtained in the literature for dark energy parameterizations that are phantom at all redshifts. But we obtained same results for dark energy parameterizations which are in phantom regime and enter in quintessence region at relatively low redshifts. We also show that in parameterizations under study, low mass halos were formed before massive halos.

    ↳ gr-qcastro-ph.COhep-phMNRAS(2019)·17 citations
16. 16*

    Wavefunctions and Yukawa Couplings on Resolutions of $T^2/{\mathbb{Z}}_N$ Orbifolds

    Tatsuo Kobayashi🇯🇵 · Hajime Otsuka🇯🇵 · Hikaru Uchida🇯🇵

    We propose matter wavefunctions on resolutions of $T^2/{\mathbb{Z}}_N$ singularities with constant magnetic fluxes. In the blow-down limit, the obtained wavefunctions of chiral zero-modes result in those on the magnetized $T^2/{\mathbb{Z}}_N$ orbifold models, but the wavefunctions of ${\mathbb{Z}}_N$-invariant zero-modes receive the blow-up effects around fixed points of $T^2/{\mathbb{Z}}_N$ orbifolds. Such blow-up effects change the selection rules and Yukawa couplings among the chiral zero-modes as well as the modular symmetry, in contrast to those on the magnetized $T^2/{\mathbb{Z}}_N$ orbifold models.

    ↳ hep-thhep-phJHEP(2019)·16 citations
17. 17*

    21-cm observations and warm dark matter models

    Alexey Boyarsky🇳🇱 · Dmytro Iakubovskyi🇩🇰 · Oleg Ruchayskiy🇩🇰 · Anton Rudakovskyi🇺🇦 · Wessel Valkenburg🇨🇭

    Observations of the redshifted 21-cm signal (in absorption or emission) allow us to peek into the epoch of "dark ages" and the onset of reionization. These data can provide a novel way to learn about the nature of dark matter, in particular about the formation of small size dark matter halos. However, the connection between the formation of structures and 21-cm signal requires knowledge of stellar to total mass relation, escape fraction of UV photons, and other parameters that describe star formation and radiation at early times. This baryonic physics depends on the properties of dark matter and in particular in warm-dark-matter (WDM) models, star formation may follow a completely different scenario, as compared to the cold-dark-matter case. We use the recent measurements by the EDGES [J. D. Bowman, A. E. E. Rogers, R. A. Monsalve, T. J. Mozdzen, and N. Mahesh, An absorption profile centred at 78 megahertz in thesky-averaged spectrum,Nature (London) 555, 67 (2018).] to demonstrate that when taking the above considerations into account, the robust WDM bounds are in fact weaker than those given by the Lyman-$\alpha$ forest method and other structure formation bounds. In particular, we show that resonantly produced 7 keV sterile neutrino dark matter model is consistent with these data. However, a holistic approach to modelling of the WDM universe holds great potential and may in the future make 21-cm data our main tool to learn about dark matter clustering properties.

    ↳ astro-ph.COhep-phPRD(2019)·34 citations
18. 18*

    The leading hadronic contribution to $(g-2{)}_{\mu }$ from lattice QCD with $N_{\mathrm{f}}=2+1$ flavours of O($a$) improved Wilson quarks

    Antoine Gérardin🇩🇪 · Marco Cè🇩🇪 · Georg von Hippel🇩🇪 · Ben Hörz🇺🇸 · Harvey B. Meyer🇩🇪 · Daniel Mohler🇩🇪 · Konstantin Ottnad🇩🇪 · Jonas Wilhelm🇩🇪 · Hartmut Wittig🇩🇪

    The comparison of the theoretical and experimental determinations of the anomalous magnetic moment of the muon $(g-2{)}_{\mu }$ constitutes one of the strongest tests of the Standard Model at low energies. In this article, we compute the leading hadronic contribution to $(g-2{)}_{\mu }$ using lattice QCD simulations employing Wilson quarks. Gauge field ensembles at four different lattice spacings and several values of the pion mass down to its physical value are used. We apply the O($a$) improvement programme with two discretizations of the vector current to better constrain the approach to the continuum limit. The electromagnetic current correlators are computed in the time-momentum representation. In addition, we perform auxiliary calculations of the pion form factor at timelike momenta in order to better constrain the tail of the isovector correlator and to correct its dominant finite-size effect. For the numerically dominant light-quark contribution, we have rescaled the lepton mass by the pion decay constant computed on each lattice ensemble. We perform a combined chiral and continuum extrapolation to the physical point, and our final result is $a_{\mu }^{\mathrm{hvp}}=(720.0\pm 12.4_{\mathrm{stat}}\pm 9.9_{\mathrm{syst}})\cdot 10^{-10}$. It contains the contributions of quark-disconnected diagrams, and the systematic error has been enlarged to account for the missing isospin-breaking effects.

    ↳ hep-lathep-phPRD(2019)·213 citations
19. 19*

    Timing Argument take on the Milky Way and Andromeda past-encounter

    David Benisty🇮🇱

    The two-body problem of $M31$ and the Milky Way (MW) galaxies with a Cosmological Constant background is studied, with emphasis on the possibility that they experienced Past Encounter (PE). PE are possible only for non-zero transverse velocity and their viability is subject to observations of the imprints of such near collisions. By implementing the Timing Argument (TA) for two isolated point bodies, it is shown that if $M31$ and the MW have had PE, then the predicted mass of the Local Group (LG) should be twice larger. Since the predicted mass is too large, the MW and $M31$ galaxies should have collided at $\sim 8Gys$. Therefore, the TA analysis show that PE is not possible for the Local Group (LG) system.

    ↳ astro-ph.GAastro-ph.COgr-qchep-phAstron.Astrophys.(2021)·19 citations
20. 20*

    The quark-mass dependence of elastic $\pi K$ scattering from QCD

    David J. Wilson🇮🇪 · Raul A. Briceno🇺🇸 · Jozef J. Dudek🇺🇸 · Robert G. Edwards🇺🇸 · Christopher E. Thomas🇬🇧

    We present a determination of the isospin-1/2 elastic $\pi K$ scattering amplitudes in S and P partial waves using lattice Quantum Chromodynamics. The amplitudes, constrained for a large number of real-valued energy points, are obtained as a function of light-quark mass, corresponding to four pion masses between 200 and 400 MeV. Below the first inelastic threshold, the P-wave scattering amplitude is dominated by a single pole singularity that evolves from being a stable bound-state at the highest quark mass into a narrow resonance that broadens as the pion and kaon masses are reduced. As in experiment, the S-wave amplitude does not exhibit an obviously resonant behavior, but instead shows a slow rise from threshold, which is not inconsistent with the presence of a $\kappa$/$K_0^{\star }(700)$-like resonance at the considered quark masses. As has been found in analyses of experimental scattering data, simple analytic continuations into the complex energy plane of precisely-determined lattice QCD amplitudes on the real energy axis are not sufficient to model-independently determine the existence and properties of this state. The spectra and amplitudes we present will serve as an input for increasingly elaborate amplitude analysis techniques that implement more of the analytic structure expected at complex energies.

    ↳ hep-lathep-phPRL(2019)·98 citations
21. 21*

    Proper Motions of the Satellites of M31

    Ben Hodkinson🇬🇧 · Jakub Scholtz🇬🇧

    We predict the range of proper motions of 19 satellite galaxies of M31 that would rotationally stabilise the M31 plane of satellites consisting of 15-20 members as identified by Ibata et al. (2013). Our prediction is based purely on the current positions and line-of-sight velocities of these satellites and the assumption that the plane is not a transient feature. These predictions are therefore independent of the current debate about the formation history of this plane. We further comment on the feasibility of measuring these proper motions with future observations by the THEIA satellite mission as well as the currently planned observations by HST and JWST.

    ↳ astro-ph.GAhep-phMNRAS(2019)·4 citations
22. 22*

    Transition form factors: ${\gamma }^{\ast }+p\to \Delta (1232)$, $\Delta (1600)$

    Ya Lu🇨🇳 · Chen Chen🇧🇷 · Zhu-Fang Cui🇨🇳 · Craig D. Roberts🇺🇸 · Sebastian M. Schmidt🇩🇪 · Jorge Segovia🇪🇸 · Hong-Shi Zong🇨🇳

    Electroproduction form factors describing the ${\gamma }^{\ast }p\to {\Delta }^{+}(1232),{\Delta }^{+}(1600)$ transitions are computed using a fully-dynamical diquark-quark approximation to the Poincaré-covariant three-body bound-state problem in relativistic quantum field theory. In this approach, the $\Delta (1600)$ is an analogue of the Roper resonance in the nucleon sector, appearing as the simplest radial excitation of the $\Delta (1232)$. Precise measurements of the ${\gamma }^{\ast }p\to {\Delta }^{+}(1232)$ transition already exist on $0\le Q^2\lesssim 8$GeV${}^2$ and the calculated results compare favourably with the data outside the meson-cloud domain. The predictions for the ${\gamma }^{\ast }p\to {\Delta }^{+}(1600)$ magnetic dipole and electric quadrupole transition form factors are consistent with the empirical values at the real photon point, and extend to $Q^2\approx 6m_p^2$, enabling a meaningful direct comparison with experiment once analysis of existing data is completed. In both cases, the electric quadrupole form factor is particularly sensitive to deformation of the $\Delta$-baryons. Interestingly, whilst the ${\gamma }^{\ast }p\to {\Delta }^{+}(1232)$ transition form factors are larger in magnitude than those for ${\gamma }^{\ast }p\to {\Delta }^{+}(1600)$ in some neighbourhood of the real photon point, this ordering is reversed on $Q^2\gtrsim 2m_p^2$, suggesting that the ${\gamma }^{\ast }p\to {\Delta }^{+}(1600)$ transition is more localised in configuration space.

    ↳ nucl-thhep-lathep-phnucl-exPRD(2019)·51 citations
23. 23*

    Describing phase transitions in field theory by self-similar approximants

    V.I. Yukalov🇷🇺 · E.P. Yukalova🇷🇺

    Self-similar approximation theory is shown to be a powerful tool for describing phase transitions in quantum field theory. Self-similar approximants present the extrapolation of asymptotic series in powers of small variables to the arbitrary values of the latter, including the variables tending to infinity. The approach is illustrated by considering three problems: (i) The influence of the coupling parameter strength on the critical temperature of the O(N)-symmetric multicomponent field theory. (ii) The calculation of critical exponents for the phase transition in the O(N)-symmetric field theory. (iii) The evaluation of deconfinement temperature in quantum chromodynamics. The results are in good agreement with the available numerical calculations, such as Monte Carlo simulations, Pade-Borel summation, and lattice data.

    ↳ cond-mat.stat-mechhep-phEPJ Web Conf.(2019)·3 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.