Wed·Oct 9, 2019Wednesday·October 9, 2019

1. 01*

   Exotic Spin-Dependent Forces from a Hidden Sector

   Alexandria Costantino🇺🇸 · Sylvain Fichet🇧🇷 · Philip Tanedo🇺🇸

   New dynamics from hidden sectors may manifest as long-range forces between visible matter particles. The well-known case of Yukawa-like potentials occurs via the exchange of a single virtual particle. However, more exotic behavior is also possible. We present three classes of exotic potentials that are generated by relativistic theories: (i) quantum forces from the loop-level exchange of two virtual particles, (ii) conformal forces from a conformal sector, and (iii) emergent forces from degrees of freedom that only exist in the infrared regime of the theory. We discuss the complementarity of spin-dependent force searches in an effective field theory framework. We identify well-motivated directions to search for exotic spin-dependent forces.

   hep-phJHEP(2020)·42 citations
2. 02*

   Walking Dynamics Guaranteed

   Jarno Rantaharju🇫🇮 · Claudio Pica🇩🇰 · Francesco Sannino🇩🇰

   We report evidence for a continuous transition from an infrared conformal phase to a chirally broken one in four dimensions. We study a model with two Dirac fermions in the adjoint representation of an SU(2) gauge interaction and a chirally symmetric four-fermion interaction. At large four-fermion coupling, the model goes through a transition into a chirally broken phase and infrared conformality is lost. We show strong evidence that this transition is continuous, which would guarantee walking dynamics within the scaling region in the chirally broken phase.

   hep-phhep-lat5 citations
3. 03*

   Spherocity study for e^{+}e^{-} Fragmentation Functions using Pythia MC generator

   H. Bello Martínez🇲🇽 · R. J. Hernández-Pinto🇲🇽 · I. León Monzón🇲🇽

   The Fragmentation Functions is one of the non-perturbative components of the QCD factorization theorem. They represents the probability of a parton carrying a fraction z of momentum to form into a particular kind of hadron. In this work, we study the jet fragmentation functions in the collisions between electrons and positrons. The jets where identified with Fastjet for different p_{Tch jet} intervals. The intervals and the final jets were reconstructed by means of the event shape T separation using spherocity variable, the study is performed under Pythia Monte Carlo event generator framework.

   hep-phPoS(2019)·1 citation
4. 04*

   Khuri-Treiman equations for $3\pi$ decays of particles with spin

   JPAC Collaboration: M. Albaladejo🇺🇸 · D. Winney🇺🇸 · I. V.~Danilkin🇩🇪 · C. Fernandez-Ramirez🇲🇽 · V. Mathieu🇪🇸 · M. Mikhasenko🇨🇭 · A. Pilloni🇮🇹 · J.A. Silva-Castro🇲🇽 · A. P. Szczepaniak🇺🇸

   Khuri-Treiman equations have proven to be a useful theoretical tool in the analysis of 3-body decays, specially into the $3\pi$ final state. In this work we present in full detail the necessary generalization of the formalism to study the decays of particles with arbitrary spin, parity, and charge conjugation. To this extent, we find it most convenient to work with helicity amplitudes instead of the so-called invariant amplitudes, specially when dealing with the unitarity relations. The isobar expansions in the three possible ($s$-, $t$-, and $u$-) final channels are related with the appropriate crossing matrices. We pay special attention to the kinematical singularities and constraints of the helicity amplitudes, showing that these can be derived by means of the crossing matrix.

   hep-phhep-exhep-thnucl-thPRD(2020)·25 citations
5. 05*

   Extraction of the CKM phase $\gamma$ from charmless two-body B meson decays

   Si-Hong Zhou🇨🇳 · Cai-Dian Lu🇨🇳

   Utilizing all the experimental measured charmless $B\to PP$, $PV$ decay modes, where $P(V)$ denotes a light pseudoscalar (vector) meson, we extract the CKM angle $\gamma$ by global fit. All the unknown hadronic parameters are fitted with $\gamma$ together from experimental data, so as to make the approach least model dependent. The different contributions for various decay modes are classified by topological weak Feynman diagram amplitudes, which are to be determined by the global fit. To improve the precision of this approach, we consider flavor SU(3) breaking effects of topological diagram amplitudes among different decay modes by including the form factors and decay constants. The fitted result for CKM angle $\gamma$ is $(69.8\pm 2.1\pm 0.9{)}^{°}$. It is consistent with the current world average with a better precision.

   hep-phhep-exCPC(2020)·9 citations
6. 06*

   Operatorial characterization of Majorana neutrinos

   Kazuo Fujikawa🇯🇵

   The Majorana neutrino ${\psi }_M(x)$ when constructed as a superposition of chiral fermions such as ${\nu }_L+C{\overline{{\nu }_L}}^T$ is characterized by $(\mathcal{C}\mathcal{P}){\psi }_M(x)(\mathcal{C}\mathcal{P}{)}^{†}=i{\gamma }^0{\psi }_M(t,-\vec{x})$, and the CP symmetry describes the entire physics contents of Majorana neutrinos. Further specifications of C and P separately could lead to difficulties depending on the choice of C and P. The conventional $\mathcal{C}{\psi }_M(x){\mathcal{C}}^{†}={\psi }_M(x)$ with well-defined P is naturally defined when one constructs the Majorana neutrino from the Dirac-type fermion. In the seesaw model of Type I or Type I+II where the same number of left- and right-handed chiral fermions appear, it is possible to use the generalized Pauli-Gursey transformation to rewrite the seesaw Lagrangian in terms of Dirac-type fermions only; the conventional C symmetry then works to define Majorana neutrinos. In contrast, the "pseudo C-symmetry" ${\nu }_{L,R}(x)\to C{\overline{{\nu }_{L,R}(x)}}^T$ (and associated "pseudo P-symmetry"), that has been often used in both the seesaw model and Weinberg's model to describe Majorana neutrinos, attempts to assign a nontrivial charge conjugation transformation rule to each chiral fermion separately. But this common construction is known to be operatorially ill-defined and, for example, the amplitude of the neutrinoless double beta decay vanishes if the vacuum is assumed to be invariant under the pseudo C-symmetry.

   hep-phhep-thEPJC(2020)·7 citations
7. 07*

   Spin polarizations under a pseudovector interaction between quarks with the Kobayashi-Maskawa-'t Hooft term in high density quark matter

   M. Morimoto (Kochi Univ., Japan)🇯🇵 · Y. Tsue (Kochi Univ., Japan)🇯🇵 · J. da Providencia (Univ. de Coimbra, Portugal)🇵🇹 · C. Providencia (Univ. de Coimbra, Portugal)🇵🇹 · M. Yamamura (Kansai Univ., Japan)🇯🇵

   A possibility of a quark spin polarization originated from a pseudovector condensate is investigated in the three-flavor Nambu-Jona-Lasinio model with the Kobayashi-Maskawa-'t Hooft interaction which leads to flavor mixing. It is shown that a pseudovector condensate related to the strange quark easily occurs compared with pseudovector condensate related to light quarks. Further, it is shown that the pseudovector condensate related to the strange quark appears at a slightly small chemical potential by the effect of the flavor mixing due to the Kobayashi-Maskawa-'t Hooft interaction.

   hep-phnucl-thIJMPE(2020)·2 citations
8. 08*

   Semiexclusive production of vector mesons in proton-proton collisions with electromagnetic dissociation

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

   We calculate distributions of different vector mesons in purely exclusive ($pp\to ppV$) and semi-exclusive ($pp\to pXV$) processes with electromagnetic dissociation of a proton. The cross section for the electromagnetic dissociation is expressed through electromagnetic structure functions of the proton. We include the transverse momentum distribution of initial photons in the associated flux. Contributions of the exclusive and semi-exclusive processes are compared for different vector mesons ($V=\varphi ,J/\psi ,{\rm Y}$). We discuss how the relative contribution of the semi-exclusive processes depends on the mass of the vector meson as well as on different kinematical variables of the vector meson ($y$, $p_t$). The ratio of semi-exclusive to exclusive contributions are shown and compared for different mesons in different variables.

   hep-phPRD(2019)·2 citations
9. 09*

   Decay properties of the $Z_c(3900)$ through the Fierz rearrangement

   Hua-Xing Chen🇨🇳

   We systematically construct all the tetraquark currents/operators of $J^{PC}=1^{+-}$ with the quark configurations $[cq][\bar{c}\bar{q}]$, $[\bar{c}q][\bar{q}c]$, and $[\bar{c}c][\bar{q}q]$ ($q=u/d$), and derive their relations through the Fierz rearrangement of the Dirac and color indices. Using the transformations of $[qc][\bar{q}\bar{c}]\to [\bar{c}c][\bar{q}q]$ and $[\bar{c}q][\bar{q}c]$, we study decay properties of the $Z_c(3900)$ as a compact tetraquark state; while using the transformation of $[\bar{c}q][\bar{q}c]\to [\bar{c}c][\bar{q}q]$, we study its decay properties as a hadronic molecular state.

   hep-phhep-exhep-latCPC(2020)·15 citations
10. 10*

    Nonstandard neutrino interactions at COHERENT, DUNE, T2HK and LHC

    Tao Han🇺🇸 · Jiajun Liao🇨🇳 · Hongkai Liu🇺🇸 · Danny Marfatia🇺🇸

    We study how nonstandard neutrino interactions (NSI) may be probed by a combination of coherent elastic neutrino-nucleus scattering, neutrino oscillation and collider data, from COHERENT, DUNE, T2HK and the high-luminosity (HL) LHC. We focus on NSI induced by a new flavored gauge boson $Z^{\prime }$ in a generic anomaly-free ultraviolet-complete model. For $Z^{\prime }$ masses above 10 GeV, the HL-LHC has the best sensitivity regardless of the flavor structure of the model. For masses between 0.01 GeV-10 GeV, current LHCb data and future COHERENT data have the best sensitivity unless the $Z^{\prime }$ couplings to the first and second generation leptons are suppressed, in which case DUNE and T2HK have the best sensitivity. For $Z^{\prime }$ masses between about 5 MeV-20 MeV, DUNE and T2HK have the best sensitivity. We also show how joint analyses of COHERENT and LHC data may constrain such models.

    hep-phhep-exJHEP(2019)·56 citations
11. 11*

    Accessing the gluonic structure of light nuclei at the Electron Ion Collider

    Heikki Mäntysaari🇫🇮 · Björn Schenke🇺🇸

    We show how exclusive vector meson production off light ions can be used to probe the spatial distribution of small-$x$ gluons in the deuteron and ${}^3$He wave functions. In particular, we demonstrate how short range repulsive nucleon-nucleon interactions affect the predicted coherent $J/\Psi$ production spectra. Fluctuations of the nucleon substructure are shown to have a significant effect on the incoherent cross section above $|t|\gtrsim 0.2{\mathrm{GeV}}^2$. By explicitly performing the JIMWLK evolution, we predict the $x$-dependence of coherent and incoherent cross sections in the EIC energy range. Besides the increase of the average size of the nucleus with decreasing $x$, both the growth of the nucleons and subnucleonic hot spots are visible in the cross sections. The decreasing length scale of color charge fluctuations with decreasing $x$ is also present, but may not be observable for $|t|<1{\mathrm{GeV}}^2$, if subnucleonic spatial fluctuations are present.

    hep-phnucl-thPRC(2020)·34 citations
12. 12*

    Interpretation of the observed ${\Lambda }_b(6146{)}^0$ and ${\Lambda }_b(6152{)}^0$ states as 1$D$ bottom baryons

    Bing Chen🇨🇳 · Si-Qiang Luo🇨🇳 · Xiang Liu🇨🇳 · Takayuki Matsuki🇯🇵

    The measured masses and strong decays of ${\Lambda }_b(6146{)}^0$ and ${\Lambda }_b(6152{)}^0$ required us to decode them as the 1$D$ excited states with $J^P=3/2^{+}$ and $J^P=5/2^{+}$, respectively. Under the suggested assignment, the masses and total decay widths of ${\Lambda }_b(6146{)}^0$ and ${\Lambda }_b(6152{)}^0$ can be explained. As a $J^P=3/2^{+}$ state, the ${\Lambda }_b(6146{)}^0$ should mainly decay into ${\Sigma }_b(5815)\pi$. However, this theoretical result is in contradiction to the measurement since no significant ${\Lambda }_b(6146{)}^0\to {\Sigma }_b(5815{)}^{\pm }{\pi }^{\mp }$ signals were observed by the LHCb. The possible explanations to this difficulty are mentioned. For completeness, we present the prediction of masses and decay widths of other unseen 1$D$ bottom baryons in this work. Our results could provide some important clues for the upcoming experiments.

    hep-phPRD(2019)·36 citations
13. 13*

    The Partonic Content of Nucleons and Nuclei

    Juan Rojo🇳🇱

    Deepening our knowledge of the partonic content of nucleons and nuclei represents a central endeavour of modern high-energy and nuclear physics, with ramifications in related disciplines such as astroparticle physics. There are two main scientific drivers motivating these investigations of the partonic structure of hadrons. On the one hand, addressing fundamental open issues in our understanding in the strong interactions such as the origin of the nucleon mass, spin, and transverse structure; the presence of heavy quarks in the nucleon wave function; and the possible onset of novel gluon-dominated dynamical regimes. On the other hand, pinning down with the highest possible precision the substructure of nucleons and nuclei is a central component for theoretical predictions in a wide range of experiments, from proton and heavy ion collisions at the Large Hadron Collider to ultra-high energy neutrino interactions at neutrino telescopes. This Article presents a succinct non-technical overview of our modern understanding of the quark, gluon, and photon substructure of nucleons and nuclei, focusing on recent trends and results and discussing future perspectives for the field.

    hep-phhep-exnucl-thOxford Research Encyclopedia of Physics(2021)·16 citations
14. 14*

    A Left-Right Mirror Symmetric Model: Common Origin of Neutrino Mass, Baryon Asymmetry and Dark Matter

    Wei-Min Yang🇨🇳

    I suggest a left-right mirror symmetric particle model as the natural and aesthetic extension of the SM. As the left-right mirror symmetry breaking, the tiny neutrino mass is generated by the radiative mechanism, the baryon asymmetry through the leptogenesis arises from the characteristic decay of the TeV-scale mirror charged lepton, and a KeV-mass sterile Dirac fermion eventually becomes the CDM. The model can completely account for the common origin of the neutrino mass, the baryon asymmetry and the dark matter, moreover, profoundly uncover the internal connections among them. Finally, I discuss several feasible approaches to test the model predictions and probe the new physics by near future experiments.

    hep-phJHEP(2020)·3 citations
15. 15*

    Modular $S_4$ and $A_4$ Symmetries and Their Fixed Points: New Predictive Examples of Lepton Mixing

    Gui-Jun Ding🇨🇳 · Stephen F. King🇬🇧 · Xiang-Gan Liu🇨🇳 · Jun-Nan Lu🇨🇳

    In the modular symmetry approach to neutrino models, the flavour symmetry emerges as a finite subgroup ${\Gamma }_N$ of the modular symmetry, broken by the vacuum expectation value (VEV) of a modulus field $\tau$. If the VEV of the modulus $\tau$ takes some special value, a residual subgroup of ${\Gamma }_N$ would be preserved. We derive the fixed points ${\tau }_S=i$, ${\tau }_{ST}=(-1+i\sqrt{3})/2$, ${\tau }_{TS}=(1+i\sqrt{3})/2$, ${\tau }_T=i\infty$ in the fundamental domain which are invariant under the modular transformations indicated. We then generalise these fixed points to ${\tau }_f=\gamma {\tau }_S$, $\gamma {\tau }_{ST}$, $\gamma {\tau }_{TS}$ and $\gamma {\tau }_T$ in the upper half complex plane, and show that it is sufficient to consider $\gamma \in {\Gamma }_N$. Focussing on level $N=4$, corresponding to the flavour group $S_4$, we consider all the resulting triplet modular forms at these fixed points up to weight 6. We then apply the results to lepton mixing, with different residual subgroups in the charged lepton sector and each of the right-handed neutrinos sectors. In the minimal case of two right-handed neutrinos, we find three phenomenologically viable cases in which the light neutrino mass matrix only depends on three free parameters, and the lepton mixing takes the trimaximal TM1 pattern for two examples. One of these cases corresponds to a new Littlest Modular Seesaw based on CSD$(n)$ with $n=1+\sqrt{6}\approx 3.45$, intermediate between CSD$(3)$ and CSD$(4)$. Finally, we generalize the results to examples with three right-handed neutrinos, also considering the level $N=3$ case, corresponding to $A_4$ flavour symmetry.

    hep-phJHEP(2019)·170 citations
16. 16*

    Heavy quark expansion for heavy-light light-cone operators

    Shuai Zhao🇺🇸

    We generalize the celebrated heavy quark expansion to nonlocal QCD operators. By taking nonlocal heavy-light current on the light-cone as an example, we confirm that the collinear singularities are common between QCD operator and the corresponding operator in heavy quark effective theory (HQET), at the leading power of $1/M$ expansion. Based on a perturbative calculation in operator form at one-loop level, a factorization formula linking QCD and HQET operators is investigated and the matching coefficient is determined. The matching between QCD and HQET light-cone distribution amplitudes (LCDAs) as well as other momentum distributions of hadron can be derived as a consequence.

    hep-phPRD(2020)·16 citations
17. 17*

    Bethe phase including proton excitations

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

    We evaluate the contribution of inelastic intermediate states (such as $p\to N^{\ast }$ excitations) to the phase between the one-photon-exchange and the `nuclear' high energy $pp$ scattering amplitudes as $t\to 0$, caused by multiphoton diagrams. It turns out to be rather small - much smaller than to have any influence on the experimental accuracy of the measurements of $\rho$, defined to be the ratio of the real to imaginary parts of the forward `nuclear' amplitude.

    hep-phPRD(2020)·7 citations
18. 18*

    An effective field theory approach to quarkonium at small transverse momentum

    Sean Fleming🇺🇸 · Yiannis Makris🇮🇹 · Thomas Mehen🇺🇸

    In this work we apply effective field theory (EFT) to observables in quarkonium production and decay that are sensitive to soft gluon radiation, in particular measurements that are sensitive to small transverse momentum. Within the EFT framework we study ${\chi }_Q$ decay to light quarks followed by the fragmentation of those quarks to light hadrons. We derive a factorization theorem that involves transverse momentum distribution (TMD) fragmentation functions and new quarkonium TMD shape functions. We derive renormalization group equations, both in rapidity and virtuality, which are used to evolve the different terms in the factorization theorem to resum large logarithms. This theoretical framework will provide a systematic treatment of quarkonium production and decay processes in TMD sensitive measurements.

    hep-phnucl-thJHEP(2020)·61 citations
19. 19*

    The light CP-even MSSM Higgs mass including N${}^3$LO+N${}^3$LL QCD corrections

    R.V. Harlander🇩🇪 · J. Klappert🇩🇪 · A. Voigt🇩🇪

    We present a calculation of the light neutral CP-even Higgs boson pole mass in the real MSSM which combines state-of-the-art EFT and fixed-order results, including the three-loop fixed-order QCD corrections as well as the resummation of logarithmic terms in the ratio of the weak to the SUSY scale up to fourth logarithmic order. This hybrid calculation should be valid for arbitrary SUSY scales above the weak scale. Comparison to the pure fixed-order and EFT results provides an estimate of their individual validity range.

    hep-phEPJC(2020)·23 citations
20. 20*

    Inhomogeneous chiral condensates in three-flavor quark matter

    Stefano Carignano🇪🇸 · Michael Buballa🇩🇪

    We investigate the effect of strange quark degrees of freedom on the formation of inhomogeneous chiral condensates in a three-flavor Nambu--Jona-Lasinio model in mean-field approximation. A Ginzburg-Landau study complemented by a stability analysis allow us to determine in a general way the location of the critical and Lifshitz points, together with the phase boundary where the (partially) chirally restored phase becomes unstable against developing inhomogeneities, without resorting to specific assumptions on the shape of the chiral condensate. We discuss the resulting phase structure and study the influence of the bare strange-quark mass $m_s$ and the axial anomaly on the size and location of the inhomogeneous phase compared to the first-order transition associated with homogeneous matter. We find that, as a consequence of the axial anomaly, critical and Lifshitz point split. For realistic strange-quark masses the effect is however very small and becomes sizeable only for small values of $m_s$.

    hep-phnucl-thPRD(2020)·40 citations
21. 21*

    Investigating the Hubble Constant Tension -- Two Numbers in the Standard Cosmological Model

    Weikang Lin🇺🇸 · Katherine J. Mack🇺🇸 · Liqiang Hou🇺🇸

    The current Hubble constant tension is usually presented by comparing constraints on $H_0$ only. However, the post-recombination background cosmic evolution is determined by two parameters in the standard $\Lambda$CDM model, the Hubble constant ($H_0$) and today's matter energy fraction (${\Omega }_{\mathrm{m}}$). If we therefore compare all constraints individually in the $H_0$-${\Omega }_{\mathrm{m}}$ plane, (1) various constraints can be treated as independently as possible, (2) single-sided constraints are easier to consider, (3) compatibility among different constraints can be viewed in a more robust way, (4) the model dependence of each constraint is clear, and (5) whether or not a nonstandard model is able to reconcile all constraints in tension can be seen more effectively. We perform a systematic comparison of different constraints in the $H_0$-${\Omega }_{\mathrm{m}}$ space based on a flat $\Lambda$CDM model, treating them as separately as possible. Constraints along different degeneracy directions consistently overlap in one region of the space, with the local measurement from Cepheid variable-calibrated supernovae being the most outlying, followed by the time-delay strong-lensing result. Considering the possibility that some nonstandard physics may reconcile the constraints, we provide a general discussion on nonstandard models with modifications at high, mid, or low redshifts, and the effect of local environmental factors. Due to the different responses of individual constraints to a modified model, it is not easy for nonstandard models to reconcile all constraints if none of them have unaccounted-for systematic effects.

    ↳ astro-ph.COhep-phApJL(2020)·56 citations
22. 22*

    Color Correlations in the Proton

    Gerald A. Miller🇺🇸

    A general QCD light front formalism to compute many-body color charge correlation functions due to quarks in the proton was constructed~\cite{Dumitru:2018vpr}. These enable new studies of color charge distributions in the nucleon. The analogies between such correlation functions to electric and magnetization charge densities in the proton and also to nucleon-nucleon correlations in the nucleus are discussed. Including the color charge correlations leads naturally to the removal of infrared divergences that occurs in two- and three-gluon exchange interactions in $q\bar{q}$-proton scattering. Extensions to include gluonic color charge correlations are discussed.

    ↳ nucl-thhep-ph0 citations
23. 23*

    Hadronic resonances production with ALICE at the LHC

    Sushanta Tripathy (for the ALICE Collaboration)🇮🇳

    Measurements of the production of short-lived hadronic resonances are used to probe the properties of the late hadronic phase in ultra-relativistic heavy-ion collisions. Since these resonances have lifetimes comparable to that of the fireball, they are sensitive to the competing effects of particle re-scattering and regeneration in the hadronic gas, which modify the observed particle momentum distributions and yields after hadronisation. Having different masses, quantum numbers and quark content, hadronic resonances carry a wealth of information on different aspects of ion-ion collisions, including the processes that determine the shapes of particle momentum spectra, insight into strangeness production and collective effects in small collision systems. We present the most recent ALICE results on $\rho (770{)}^0$, K*(892)${}^0$, $\varphi (1020)$, $\Sigma (1385{)}^{\pm }$, $\Lambda (1520)$, $\Xi (1530{)}^0$ and $\Xi (1820)$ production at the LHC. They include measurements performed in pp, p--Pb and Pb--Pb collisions at different energies, as well as the latest results from the LHC Run 2 with Xe--Xe collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.44 TeV and with Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV. Collision energy, centrality and multiplicity differential measurements integrated yields and particle ratios are discussed in detail. A critical overview of these results are given through comparisons to measurements from other experiments and theoretical models.

    ↳ hep-exhep-phnucl-exSpringer Proc.Phys.(2020)·1 citation
24. 24*

    Electromagnetic finite-size effects to the hadronic vacuum polarisation

    Nils Hermansson-Truedsson🇸🇪 · Johan Bijnens🇸🇪 · James Harrison🇬🇧 · Tadeusz Janowski🇬🇧 · Andreas Jüttner🇬🇧 · Antonin Portelli🇬🇧

    In order to reach (sub-)per cent level precision in lattice calculations of the hadronic vacuum polarisation, isospin breaking corrections must be included. This requires introducing QED on the lattice, and the associated finite-size effects are potentially large due to the absence of a mass gap. This means that the finite-size effects scale as an inverse polynomial in $L$ rather than being exponentially suppressed. Considering the $\mathcal{O}(\alpha )$ corrected hadronic vacuum polarisation in QED${}_{\mathrm{L}}$ with scalar QED as an effective theory, we show that the first possible term, which is of order $1/L^2$, vanishes identically so that the finite-size effects start at order $1/L^3$. This cancellation is understood from the neutrality of the currents involved, and we show that this cancellation is universal by also including form factors for the pions. We find good numerical agreement with lattice perturbation theory calculations, as well as, up to exponentially suppressed terms, scalar QED lattice simulations.

    ↳ hep-lathep-phPoS(2019)·2 citations
25. 25*

    Lifetime estimations and a non-monotonic initial energy density in heavy ion collisions at RHIC and LHC

    G. Kasza🇭🇺 · T. Csorgo🇭🇺

    We highlight some connections between the final state hadronic observables and the initial conditions using a recently found new exact family of solutions of relativistic hydrodynamics. These relations provide explicit examples of the scaling behaviour in relativistic hydrodynamics and may provide an advanced estimate of the lifetime and the initial energy density in $\sqrt{s_{NN}}=62.4$, $130$, and $200$ GeV Au+Au collisions at RHIC and $\sqrt{s_{NN}}=5.0$ TeV Pb+Pb and $5.44$ TeV Xe+Xe as well as $\sqrt{s}=7$, $8$ and $13$ TeV p+p collisions at LHC energies. A surprising result is that these advanced estimates yield a non-monotonic increase of the initial energy density with increasing collision energy at the RHIC energy range.

    ↳ nucl-thhep-exhep-phnucl-exPhys.Part.Nucl.(2020)·0 citations
26. 26*

    One-Loop Yang-Mills Integrands from Scattering Equations

    Johannes Agerskov🇩🇰 · N. E. J. Bjerrum-Bohr🇩🇰 · Humberto Gomez🇩🇰 · Cristhiam Lopez-Arcos🇨🇴

    We investigate in the context of the scattering equations, how one-loop linear propagator integrands in gauge theories can be linked to integrands with quadratic propagators using a double forward limit. We illustrate our procedure through examples and demonstrate how the different parts of the derived quadratic integrand are consistent with cut-integrands derived from four-dimensional generalized unitarity. We also comment on applications and discuss possible further generalizations.

    ↳ hep-thgr-qchep-phPRD(2020)·21 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.