Wed·Aug 19, 2020Wednesday·August 19, 2020

1. 01*

   Impressions of the Continuum Bound State Problem in QCD

   Si-Xue Qin🇨🇳 · Craig D. Roberts🇨🇳

   Modern and anticipated facilities will deliver data that promises to reveal the innermost workings of quantum chromodynamics (QCD). In order to fulfill that promise, phenomenology and theory must reach a new level, limiting and overcoming model-dependence, so that clean lines can be drawn that connect the data with QCD itself. Progress in that direction, made using continuum methods for the hadron bound-state problem, is sketched herein.

   hep-phhep-exhep-latnucl-ex+1Chin.Phys.Lett.(2020)·77 citations
2. 02*

   Diquark Correlations in Hadron Physics: Origin, Impact and Evidence

   M. Yu. Barabanov🇷🇺 · M. A. Bedolla🇲🇽 · W. K. Brooks🇨🇱 · G. D. Cates🇺🇸 · C. Chen🇩🇪 · Y. Chen🇨🇳 · E. Cisbani🇮🇹 · M. Ding🇮🇹 · G. Eichmann🇵🇹 · R. Ent🇺🇸 · J. Ferretti🇫🇮 · R. W. Gothe🇺🇸 and 15 other authors

   The last decade has seen a marked shift in how the internal structure of hadrons is understood. Modern experimental facilities, new theoretical techniques for the continuum bound-state problem and progress with lattice-regularised QCD have provided strong indications that soft quark+quark (diquark) correlations play a crucial role in hadron physics. For example, theory indicates that the appearance of such correlations is a necessary consequence of dynamical chiral symmetry breaking, viz. a corollary of emergent hadronic mass that is responsible for almost all visible mass in the universe; experiment has uncovered signals for such correlations in the flavour-separation of the proton's electromagnetic form factors; and phenomenology suggests that diquark correlations might be critical to the formation of exotic tetra- and penta-quark hadrons. A broad spectrum of such information is evaluated herein, with a view to consolidating the facts and therefrom moving toward a coherent, unified picture of hadron structure and the role that diquark correlations might play.

   hep-phhep-exhep-latnucl-ex+1PPNP(2021)·187 citations
3. 03*

   The possible tetraquark states $cc\bar{c}\bar{c}$ observed by the LHCb experiment

   Kuang-Ta Chao🇨🇳 · Shi-Lin Zhu🇨🇳

   We give a brief comment on the possible tetraquark states $cc\bar{c}\bar{c}$ observed by the LHCb experiment.

   hep-phhep-exSci.Bull.(2020)·52 citations
4. 04*

   Model-independent approach for incorporating interference effects in collider searches for new resonances

   Stefano Frixione🇮🇹 · Lydia Roos🇫🇷 · Edmund Ting🇦🇺 · Eleni Vryonidou🇨🇭 · Martin White🇦🇺 · Anthony G. Williams🇦🇺

   The presence of large-mass resonances in the data collected at the Large Hadron Collider would provide direct evidence of physics beyond the Standard Model. A key challenge in current resonance searches at the LHC is the modelling of signal--background interference effects, which can severely distort the shape of the reconstructed invariant mass distribution relative to the case where there is no interference. Such effects are strongly dependent on the beyond the Standard Model theory that must be considered as unknown if one aims to minimise any theoretical bias on the search results. In this paper, we describe a procedure which employs a physically-motivated, model-independent template functional form that can be used to model interference effects, both for the characterisation of positive discoveries, and in the presentation of null results. We illustrate the approach with the example of a scalar resonance decaying into a pair of photons.

   hep-phEPJC(2020)·2 citations
5. 05*

   Polarization effects in the search for dark vector boson at $e^{+}{e}^{-}$ colliders

   Fei-Fan Lee🇨🇳 · Guey-Lin Lin🇹🇼 · Vo Quang Nhat🇹🇼

   We argue that the search for dark vector boson through $e^{+}{e}^{-}\to Z_d\gamma$ can determine the Lorentz structure of $Z_d{l}^{+}{l}^{-}$ couplings with the detection of leptonic decays $Z_d\to l^{+}{l}^{-}$. We assume a general framework that the dark vector boson interacts with ordinary fermions through vector and axial-vector couplings. As a consequence of Ward-Takahashi identity, $Z_d$ is transversely polarized in the limit $m_{Z_d}\ll \sqrt{s}$. On the other hand, the fraction of longitudinal $Z_d$ is non-negligible for $m_{Z_d}$ comparable to $\sqrt{s}$. Such polarization effects can be analyzed through angular distributions of final-state particles in $Z_d$ decays. Taking $l^{\pm }\equiv {\mu }^{\pm }$, we study the correlation between $Z_d$ angle relative to $e^{-}$ beam direction in $e^{+}{e}^{-}$ CM frame and ${\mu }^{-}$ angle relative to the boost direction of $Z_d$ in $Z_d$ rest frame. This correlation is shown to be useful for probing the Lorentz structure of $Z_d{l}^{+}{l}^{-}$ couplings. We discuss the measurement of such correlation in Belle II detector, taking into account the detector acceptance and energy resolution.

   hep-phhep-exPRD(2021)·5 citations
6. 06*

   Molecular picture for $X_0(2900)$ and $X_1(2900)$

   Jun He🇨🇳 · Dian-Yong Chen🇨🇳

   Inspired by the newly observed $X_0(2900)$ and $X_1(2900)$ at LHCb, the $K^{\ast }{\bar{D}}^{\ast }$ and $K{\bar{D}}_1$ interactions are studied in the quasipotential Bethe-Salpeter equation approach combined with the one-boson-exchange model. The bound and virtual states from the interactions are searched for as the poles in the complex energy plane of scattering amplitude. A bound state with $I(J^P)=0(0^{+})$ and a virtual state with $0(1^{-})$ are produced from the $K^{\ast }{\bar{D}}^{\ast }$ interaction and $K{\bar{D}}_1$ interaction, and can be related to the $X_0(2900)$ and $X_1(2900)$ observed at LHCb, respectively. A bound state with $I(J^P)=0(1^{+})$ and a virtual state with $I(J^P)=0(2^{+})$ are also predicted from the $K^{\ast }{\bar{D}}^{\ast }$ interaction with a small $\alpha$ value, which can be searched in future experiments.

   hep-phCPC(2021)·72 citations
7. 07*

   Analysis of the $X_0(2900)$ as the scalar tetraquark state via the QCD sum rules

   Zhi-Gang Wang🇨🇳

   In this article, we study the axialvector-diquark-axialvector-antidiquark ($AA$) type and scalar-diquark-scalar-antidiquark ($SS$) type fully open flavor $cs\bar{u}\bar{d}$ tetraquark states with the spin-parity $J^P=0^{+}$ via the QCD sum rules. The predicted masses $M_{AA}=2.91\pm 0.12\mathrm{GeV}$ and $M_{SS}=3.05\pm 0.10\mathrm{GeV}$ support assigning the $X_0(2900)$ to be the $AA$-type scalar $cs\bar{u}\bar{d}$ tetraquark state.

   hep-phInt.J.Mod.Phys.A(2020)·81 citations
8. 08*

   All-plus helicity off-shell gauge invariant multigluon amplitudes at one loop

   Etienne Blanco🇵🇱 · Andreas van Hameren🇵🇱 · Piotr Kotko🇵🇱 · Krzysztof Kutak🇵🇱

   We calculate one loop scattering amplitudes for arbitrary number of positive helicity on-shell gluons and one off-shell gluon treated within the quasi-multi Regge kinematics. The result is fully gauge invariant and possesses the correct on-shell limit. Our method is based on embedding the off-shell process, together with contributions needed to retain gauge invariance, in a bigger fully on-shell process with auxiliary quark or gluon line.

   hep-phJHEP(2020)·17 citations
9. 09*

   Mixed state geometric phase for neutrino oscillations

   Sandeep Joshi🇮🇳

   The geometric picture of neutrino oscillations offers a unique way to study the quantum mechanics of this phenomenon. In this picture, the propagation of a neutrino beam is described by a density matrix evolving in a state space with non-trivial geometry. We derive explicit expressions of the mixed state geometric phase which arise during such an evolution for both two and three flavor neutrino oscillations. We show that, in the case of two flavor neutrino oscillations, the geometric phase is independent of the Majorana phase and it can be used as a measure of coherence of the neutrino beam.

   hep-phquant-phPLB(2020)·7 citations
10. 10*

    Strong decays of ${\bar{D}}^{\ast }{K}^{\ast }$ molecules and the newly observed $X_{0,1}$ states

    Yin Huang🇨🇳 · Jun-Xu Lu🇨🇳 · Ju-Jun Xie🇨🇳 · Li-Sheng Geng🇨🇳

    Lately, the LHCb Collaboration reported the discovery of two new states in the $B^{+}\to D^{+}{D}^{-}{K}^{+}$ decay, i.e., $X_0(2866)$ and $X_1(2904)$. In the present work, we study whether these states can be understood as $D^{\ast }{\bar{K}}^{\ast }$ molecules from the perspective of their two-body strong decays into $D^{-}{K}^{+}$ via triangle diagrams and three-body decays into $D^{\ast }\bar{K}\pi$. The coupling of the two states to $D^{\ast }{\bar{K}}^{\ast }$ are determined from the Weinberg compositeness condition, while the other relevant couplings are well known. The obtained strong decay width for the $X_0(2866)$, in marginal agreement with the experimental value within the uncertainty of the model, hints at a large $D^{\ast }{\bar{K}}^{\ast }$ component in its wave function. On the other hand, the strong decay width for the $X_1(2904)$, much smaller than its experimental counterpart, effectively rules out its assignment as a $D^{\ast }{\bar{K}}^{\ast }$ molecule.

    hep-phhep-exEPJC(2020)·84 citations
11. 11*

    The time-dependent angular analysis of $B_d\to K_S\ell \ell$, a new benchmark for new physics

    Sébastien Descotes-Genon🇫🇷 · Martín Novoa-Brunet🇫🇷 · K. Keri Vos🇩🇪

    We consider the time-dependent analysis of $B_d\to K_S\ell \ell$ taking into account the time-evolution of the $B_d$ meson and its mixing into ${\bar{B}}_d$. We discuss the angular conventions required to define the angular observables in a transparent way with respect to CP conjugation. The inclusion of time evolution allows us to identify six new observables, out of which three could be accessed from a time-dependent tagged analysis. We also show that these observables could be obtained by time-integrated measurements in a hadronic environment if flavour tagging is available. We provide simple and precise predictions for these observables in the SM and in NP models with real contributions to SM and chirally flipped operators, which are independent of form factors and charm-loop contributions. As such, these observables provide robust and powerful cross-checks of the New Physics scenarios currently favoured by global fits to $b\to s\ell \ell$ data. In addition, we discuss the sensitivity of these observables with respect to NP scenarios involving scalar and tensor operators, or CP-violating phases. We illustrate how these new observables can provide a benchmark to discriminate among the various NP scenarios in $b\to s\mu \mu$. We discuss the extension of these results for $B_s$ decays into $f_0$, $\eta$ or ${\eta }^{\prime }$.

    hep-phJHEP(2021)·29 citations
12. 12*

    Two-pole structures in a relativistic Friedrichs-Lee-QPC scheme

    Zhi-Yong Zhou🇨🇳 · Zhiguang Xiao🇨🇳

    A general appearance of two-pole structures is exhibited in a relativistic Friedrichs-Lee model combined with a relativistic quark pair creation model in a consistent manner. This kind of two-pole structure could be found when a $q\bar{q}$ state couples to the open-flavor continuum state in the $S$ partial wave. We found that many enigmatic states, such as $f_0(500)/\sigma$, $K_0^{\ast }(700)/\kappa$, $a_0(980)$, $f_0(980)$, $D_0^{\ast }(2300)$, $D_{s0}^{\ast }(2317)$, and $X(3872)$, together with another higher state for each, all result from this kind of two-pole structures. Furthermore, an interesting observation is that this kind of two-pole structure will contribute roughly a total of 180${}^{\circ }$ phase shift for the scattering process in a single channel approximation. This relativistic scheme may provide more insights into the understanding of the properties of non-$q\bar{q}$ state. It is also suggested that such two-pole structure could be a common phenomenon which deserves studying both from theoretical and experimental perspectives.

    hep-phhep-exhep-latnucl-ex+1EPJC(2021)·23 citations
13. 13*

    Discovery potentials of double-charm tetraquarks

    Qin Qin🇨🇳 · Yin-Fa Shen🇨🇳 · Fu-Sheng Yu🇨🇳

    In this study, we investigate the discovery potential of double-charm tetraquarks $T_{[\bar{q}{\bar{q}}^{\prime }]}^{\{cc\}}$. We find that their production cross sections at the LHCb with $\sqrt{s}=13$ TeV reach $\mathcal{O}(10^4)$ pb, which indicates that the LHCb has collected $\mathcal{O}(10^8)$ such particles. Through the decay channels of $T_{[\bar{u}\bar{d}]}^{\{cc\}}\to D^{+}{K}^{-}{\pi }^{+}$ or $D^0{D}^{+}\gamma$ (if stable) or $T_{[\bar{u}\bar{d}]}^{\{cc\}}\to D^0{D}^{\ast +}\to D^0{D}^0{\pi }^{+}$ (if unstable), it is highly expected that they get discovered at the LHCb in the near future. We also discuss the productions and decays of the double-charm tetraquarks at future Tera-$Z$ factories.

    hep-phhep-exCPC(2021)·83 citations
14. 14*

    Reconciling hints on axion-like-particles from high-energy gamma rays with stellar bounds

    Gautham Adamane Pallathadka🇮🇳 · Francesca Calore🇫🇷 · Pierluca Carenza🇮🇹 · Maurizio Giannotti🇺🇸 · Dieter Horns🇩🇪 · Julian Kuhlmann🇩🇪 · Jhilik Majumdar🇩🇪 · Alessandro Mirizzi🇮🇹 · Andreas Ringwald🇩🇪 · Anton Sokolov🇩🇪 · Franziska Stief🇩🇪 · Qixin Yu🇨🇳

    It has been recently claimed by two different groups that the spectral modulation observed in gamma rays from Galactic pulsars and supernova remnants can be due to conversion of photons into ultra-light axion-like-particles (ALPs) in large-scale Galactic magnetic fields. While we show the required best-fit photon-ALP coupling, $g_{a\gamma }\sim 2\times 10^{-10}$ GeV${}^{-1}$, to be consistent with constraints from observations of photon-ALPs mixing in vacuum, this is in conflict with other bounds, specifically from the CAST solar axion limit, from the helium-burning lifetime in globular clusters, and from the non-observations of gamma rays in coincidence with SN 1987A. In order to reconcile these different results, we propose that environmental effects in matter would suppress the ALP production in dense astrophysical plasma, allowing to relax previous bounds and make them compatible with photon-ALP conversions in the low-density Galactic medium. If this explanation is correct, the claimed ALP signal would be on the reach of next-generations laboratory experiments such as ALPS II.

    hep-phastro-ph.HEJCAP(2021)·33 citations
15. 15*

    Phenomenological studies on the ${\bar{B}}^0\to [K^{-}{\pi }^{+}{]}_{S/V}[{\pi }^{+}{\pi }^{-}{]}_{V/S}\to K^{-}{\pi }^{+}{\pi }^{+}{\pi }^{-}$ decay

    Jing-Juan Qi🇨🇳 · Zhen-Yang Wang🇨🇳 · Zhu-Feng Zhang🇨🇳 · Xin-Heng Guo🇨🇳

    Within the quasi-two-body decay model, we study the localized $CP$ violation and branching fraction of the four-body decay ${\bar{B}}^0\to [K^{-}{\pi }^{+}{]}_{S/V}[{\pi }^{+}{\pi }^{-}{]}_{V/S}\to K^{-}{\pi }^{+}{\pi }^{-}{\pi }^{+}$ when $K^{-}{\pi }^{+}$ and ${\pi }^{-}{\pi }^{+}$ pair invariant masses are $0.35<m_{K^{-}{\pi }^{+}}<2.04\mathrm{GeV}$ and $0<m_{{\pi }^{-}{\pi }^{+}}<1.06\mathrm{GeV}$, with the pairs being dominated by the ${\bar{K}}_0^{\ast }(700{)}^0$, ${\bar{K}}^{\ast }(892{)}^0$, ${\bar{K}}^{\ast }(1410{)}^0$, ${\bar{K}}_0^{\ast }(1430)$ and ${\bar{K}}^{\ast }(1680{)}^0$, and $f_0(500)$, ${\rho }^0(770)$ , $\omega (782)$ and $f_0(980)$ resonances, respectively. When dealing with the dynamical functions of these resonances, $f_0(500)$, ${\rho }^0(770)$, $f_0(980)$ and ${\bar{K}}_0^{\ast }(1430)$ are modeled with the Bugg model, Gounaris-Sakurai function, Flatt$\acute{\mathrm{e}}$ formalism and LASS lineshape, respectively, while others are described by the relativistic Breit-Wigner function. Adopting the end point divergence parameters ${\rho }_A\in [0,0.5]$ and ${\varphi }_A\in [0,2\pi ]$, our predicted results are ${\mathcal{A}}_{\mathcal{C}\mathcal{P}}({\bar{B}}^0\to K^{-}{\pi }^{+}{\pi }^{+}{\pi }^{-})\in [-0.383,0.421]$ and $\mathcal{B}({\bar{B}}^0\to K^{-}{\pi }^{+}{\pi }^{+}{\pi }^{-})\in [7.36,199.69]\times 10^{-8}$ based on the hypothetical $q\bar{q}$ structures for the scalar mesons in the QCD factorization approach. Meanwhile, we calculate the $CP$ violating asymmetries and branching fractions of the two-body decays ${\bar{B}}^0\to SV(VS)$ and all the individual four-body decays ${\bar{B}}^0\to SV(VS)\to K^{-}{\pi }^{+}{\pi }^{-}{\pi }^{+}$, respectively. Our theoretical results for the two-body decays ${\bar{B}}^0\to {\bar{K}}^{\ast }(892{)}^0$$f_0(980)$, ${\bar{B}}^0\to {\bar{K}}_0^{\ast }(1430{)}^0$$\omega (782)$, ${\bar{B}}^0\to {\bar{K}}^{\ast }(892{)}^0{f}_0(980)$, ${\bar{B}}^0\to {\bar{K}}_0^{\ast }(1430{)}^0\rho$,

    hep-phCPC(2021)·8 citations
16. 16*

    de Sitter Bubbles and the Swampland

    Alek Bedroya🇺🇸 · Miguel Montero🇺🇸 · Cumrun Vafa🇺🇸 · Irene Valenzuela🇺🇸

    A number of Swampland conjectures and in particular the Trans-Planckian Censorship Conjecture (TCC) suggest that de Sitter space is highly unstable if it exists at all. In this paper we construct effective theories of scalars rolling on potentials which are dual to a chain of short-lived dS spaces decaying from one to the next through a cascade of non-perturbative nucleation of bubbles. We find constraints on the effective potential resulting from various swampland criteria, including TCC, Weak Gravity Conjecture and Distance Conjecture. Surprisingly we find that TCC essentially incorporates all the other ones, and leads to a subclass of possible dual effective potentials. These results marginally rule out emergence of eternal inflation in the dual effective theory. We discuss some cosmological implications of our observations.

    ↳ hep-thhep-phFortsch.Phys.(2020)·31 citations
17. 17*

    Bulk observables at 5.02 TeV using quasiparticle anisotropic hydrodynamics

    Mubarak Alqahtani🇸🇦 · Michael Strickland🇺🇸

    We present comparisons between 3+1D quasiparticle anisotropic hydrodynamics (aHydroQP) predictions for a large set of bulk observables and experimental data collected in 5.02 TeV Pb-Pb collisions. We make aHydroQP predictions for identified hadron spectra, identified hadron average transverse momentum, charged particle multiplicity as a function of pseudorapidity, the kaon-to-pion ($K/\pi$) and proton-to-pion ($p/\pi$) ratios, and integrated elliptic flow. We compare to data collected by the ALICE collaboration in 5.02 TeV Pb-Pb collisions. We find that these bulk observables are quite well described by aHydroQP with an assumed initial central temperature of $T_0=630$ MeV at ${\tau }_0=0.25$ fm/c and a constant specific shear viscosity of $\eta /s=0.159$ and a peak specific bulk viscosity of $\zeta /s=0.048$. In particular, we find that the momentum dependence of the kaon-to-pion ($K/\pi$) and proton-to-pion ($p/\pi$) ratios reported recently by the ALICE collaboration are extremely well described by aHydroQP in the most central collisions.

    ↳ nucl-thhep-phEPJC(2021)·43 citations
18. 18*

    Color superconductivity with self-consistent NJL-type model

    Li-Qun Su🇨🇳 · Chao Shi🇨🇳 · Yong-Hui xia🇨🇳 · Hongshi Zong🇨🇳

    In this paper, the NJL-type model is used to investigate the color superconductivity. The four-fermion interactions of the NJL-type model are Fierz-transformed into two different classes, i.e., the quark-antiquark and the quark-quark interaction channels, associated with the chiral symmetry breaking and color superconductivity respectively. We conclude that the weighting factor between quark-antiquark and quark-quark interaction channels has significance on the phase structure when the mean-field approximation is employed, and the baryon number density gives a tight constraint on the weighting factor of quark-antiquark interaction channels. Besides, the susceptibilities show that the color superconducting phase transition is of the second-order and takes place before the chiral crossover transition as quark number density increases. In the end, we study the critical temperatures $T_c$ of the color superconductivity and it agrees with the perturbative result of diquark condensate $\Delta \approx 0.57T_c$.

    ↳ nucl-thhep-phPRD(2020)·12 citations
19. 19*

    Casimir force on a light front

    S.S. Chabysheva🇺🇸 · J.R. Hiller🇺🇸

    Depending on the point of view, the Casimir force arises from variation in the energy of the quantum vacuum as boundary conditions are altered or as an interaction between atoms in the materials that form these boundary conditions. Standard analyses of such configurations are usually done in terms of ordinary, equal-time (Minkowski) coordinates. However, physics is independent of the coordinate choice, and an analysis based on light-front coordinates, where $x^{+}\equiv t+z/c$ plays the role of time, is equally valid. After a brief historical introduction, we illustrate and compare equal-time and light-front calculations of the Casimir force.

    ↳ hep-thhep-phPPNP(2021)·1 citation
20. 20*

    Relativistic Kelvin circulation theorem for ideal Magnetohydrodynamics

    Jianfei Wang🇨🇳 · Shi Pu🇨🇳

    We have studied the relativistic Kelvin circulation theorem for ideal Magnetohydrodynamics. The relativistic Kelvin circulation theorem is a conservation equation for the called $T$-vorticity. We have briefly reviewed the ideal magnetohydrodynamics in relativistic heavy ion collisions. The highlight of this work is that we have obtained the general expression of relativistic Kelvin circulation theorem for ideal Magnetohydrodynamics. We have also applied the analytic solutions of ideal magnetohydrodynamics in Bjorken flow to check our results. Our main results can also be implemented to relativistic magnetohydrodynamics in relativistic heavy ion collisions.

    ↳ nucl-thhep-phNucl.Phys.Rev.(2020)·1 citation
21. 21*

    Multiplicity and pseudorapidity density distributions of charged particles produced in pp, pA and AA collisions at RHIC \& LHC energies

    Sumit Basu🇺🇸 · Sanchari Thakur🇮🇳 · Tapan K. Nayak🇨🇭 · Claude A. Pruneau🇺🇸

    Multiplicity and pseudorapidity ($\eta$) density ($d{N}_{\mathrm{ch}}/d\eta$) distributions of charged hadrons provide key information towards understanding the particle production mechanisms and initial conditions of high-energy heavy-ion collisions. However, detector constraints limit the $\eta$-range across which charged particle measurements can be carried out. Extrapolating the measured distributions to large $\eta$-range by parameterizing measured distributions and by using calculations from event generators, we characterize the production of charged particles over the full kinematic range. In the present study, we use three different ans$\ddot{\mathrm{a}}$tze to obtain quantitative descriptions of the shape of pseudorapidity distributions of charged hadrons produced in pp, p-A, and A-A collisions for beam energies ($\sqrt{s_{\mathrm{NN}}}$) ranging from a few GeV to a few TeV corresponding to RHIC and LHC energies. We study the limiting fragmentation behavior in these collisions and report evidence for participant-scaling violations in high-energy collisions at the TeV scale. We additionally examine measured pseudorapidity distributions to constrain models describing initial conditions of particle production. We predict the centrality dependence of charged particle multiplicity distributions at FAIR and NICA energies and give an estimation of charged particle multiplicity at $\eta =0$ for the proposed HE-LHC and FCC energies.

    ↳ nucl-exhep-exhep-phJ.Phys.G(2020)·19 citations
22. 22*

    Spectral properties of local gauge invariant composite operators in the $SU(2)$ Yang--Mills--Higgs model

    D. Dudal🇧🇪 · D.M. van Egmond🇧🇷 · M.S. Guimaraes🇧🇷 · L.F. Palhares🇧🇷 · G. Peruzzo🇧🇷 · S.P. Sorella🇧🇷

    The spectral properties of a set of local gauge (BRST) invariant composite operators are investigated in the $SU(2)$ Yang--Mills--Higgs model with a single Higgs field in the fundamental representation, quantized in the 't Hooft $R_{\xi }$-gauge. These operators can be thought of as a BRST invariant version of the elementary fields of the theory, the Higgs and gauge fields, with which they share a gauge independent pole mass. The two-point correlation functions of both BRST invariant composite operators and elementary fields, as well as their spectral functions, are investigated at one-loop order. It is shown that the spectral functions of the elementary fields suffer from a strong unphysical dependence from the gauge parameter $\xi$, and can even exhibit positivity violating behaviour. In contrast, the BRST invariant local operators exhibit a well defined positive spectral density.

    ↳ hep-thhep-lathep-phEPJC(2021)·29 citations
23. 23*

    Determining the Hubble Constant without the Sound Horizon: Measurements from Galaxy Surveys

    Oliver H. E. Philcox🇺🇸 · Blake D. Sherwin🇬🇧 · Gerrit S. Farren🇬🇧 · Eric J. Baxter🇺🇸

    Two sources of geometric information are encoded in the galaxy power spectrum: the sound horizon at recombination and the horizon at matter-radiation equality. Analyzing the BOSS DR12 galaxy power spectra using perturbation theory with ${\Omega }_m$ priors from Pantheon supernovae but no priors on ${\Omega }_b$, we obtain constraints on $H_0$ from the second scale, finding $H_0=65.1_{-5.4}^{+3.0}\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$; this differs from the best-fit of SH0ES at 95\% confidence. Similar results are obtained if ${\Omega }_m$ is constrained from uncalibrated BAO: $H_0=65.6_{-5.5}^{+3.4}\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$. Adding the analogous lensing results from Baxter \& Sherwin 2020, the posterior shifts to $70.6_{-5.0}^{+3.7}\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$. Using mock data, Fisher analyses, and scale-cuts, we demonstrate that our constraints do not receive significant information from the sound horizon scale. Since many models resolve the $H_0$ controversy by adding new physics to alter the sound horizon, our measurements are a consistency test for standard cosmology before recombination. A simple forecast indicates that such constraints could reach ${\sigma }_{H_0}\simeq 1.6\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ in the era of Euclid.

    ↳ astro-ph.COastro-ph.GAastro-ph.IMgr-qc+1PRD(2021)·98 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.