Thu·Jan 20, 2022Thursday·January 20, 2022

1. 01*

   Exotic hadrons in heavy ion collisions

   Luciano M. Abreu🇧🇷

   Nucleus-nucleus collisions offer a great opportunity for analyzing and determining the intrinsic nature of heavy and exotic hadrons. In this sense, here we discuss how the production and dissociation of hadron states are affected by reactions during the expansion of hadronic matter in a heavy-ion collision environment. We give emphasis to recent works on exotic states, revisiting as a case study the time evolution of the abundances of the $X_{0,1}(2900)$ states.

   hep-phPoS(2022)·2 citations
2. 02*

   Landscape of heavy baryons from the perspective of the chiral quark-soliton model

   Maxim V. Polyakov🇩🇪 · Michal Praszalowicz🇵🇱

   We employ the chiral quark-soliton model and the heavy quark symmetry to describe spectra of charm and beauty baryons. Heavy baryons can be classified according to the SU(3) representations of the light sector. We argue that recently discovered ${\Xi }_b$ states can be interpreted as negative parity excited anti-triplets or sextets, and the ${\Sigma }_b$ states as negative parity sextets. Consequences of such assignments for the decay patterns are discussed and also predictions of masses of the yet unmeasured sextet members are given.

   hep-phPRD(2022)·10 citations
3. 03*

   Bubble Nucleation to All Orders

   Andreas Ekstedt🇸🇪

   This paper extends classical results by Langer and Kramers and combines them with modern methods from high-temperature field theory. Assuming Langevin dynamics, the end-product is an all-orders description of bubble-nucleation at high temperatures. Specifically, it's shown that equilibrium and non-equilibrium effects factorize to all orders, and that the nucleation rate splits into a statistical and a dynamical prefactor. The derivation clarifies, and incorporates, higher-order corrections from zero-modes. The rate is also shown to be real to all orders in perturbation theory. The methods are applied to several models. As such, Feynman rules are given; the relevant power-counting is introduced; RG invariance is shown; the connection with the effective action is discussed, and an explicit construction of propagators in an inhomogeneous background is given. The formalism applies to both phase and Sphaleron transitions. While mainly focused on field theory, the methods are applicable to finite-dimensional systems. Finally, as this paper assumes an effective Langevin description, all results only hold within this framework.

   hep-phhep-thJHEP(2022)·47 citations
4. 04*

   Analysis of $B_s\to \varphi \nu \bar{\nu }$ at CEPC

   Lingfeng Li🇺🇸 · Manqi Ruan🇨🇳 · Yudong Wang🇨🇳 · Yuexin Wang🇨🇳

   The rare $b\to s\nu \bar{\nu }$ decays are sensitive to contributions of new physics (NP) and helpful to resolve the puzzle of multiple $B$ flavor anomalies. In this work, we propose to study the $b\to s\nu \bar{\nu }$ transition at a future lepton collider operating at the $Z$ pole through the $B_s\to \varphi \nu \bar{\nu }$ decay. Using the $B_s\to \varphi$ decay form factors from lattice simulations, we first update the SM prediction of BR($B_s\to \varphi \nu \bar{\nu }{)}_{\mathrm{SM}}=(9.93\pm 0.72)\times 10^{-6}$ and the corresponding $\varphi$ longitudinal polarization fraction $F_{L,\mathrm{SM}}=0.53\pm 0.04$. Our analysis uses the full CEPC simulation samples with a net statistic of $\mathcal{O}(10^9)$ $Z$ decays. Precise $\varphi$ and $B_s$ reconstructions are used to suppress backgrounds. The results show that BR($B_s\to \varphi \nu \bar{\nu })$ can be measured with a statistical uncertainty of $\mathcal{O}(\%)$ and an $S/B$ ratio of $\mathcal{O}(1)$ at the CEPC. The quality measures for the event reconstruction are also derived. By combining the measurement of BR($B_s\to \varphi \nu \bar{\nu })$ and $F_L$, the constraints on the effective theory couplings at low energy are given.

   hep-phhep-exPRD(2022)·23 citations
5. 05*

   LHC signatures of sterile neutrinos in a minimal radiative extended seesaw framework

   Sudhanwa Patra🇮🇳 · Utkarsh Patel🇮🇳 · Purushottam Sahu🇮🇳

   The presence of small neutrino masses and flavour mixings can be accounted for naturally in various models about extensions of the standard model, particularly in the seesaw mechanism models. In this work, we present a minimally extended seesaw framework with two right-handed neutrinos, where the active neutrino masses are derived in the radiative regime. Using the framework it can be shown that within certain mass limits, the light neutrino mass term can approach a form that is similar to its form under the type-I seesaw mechanism. Apart from this, we show that the decay width of right-handed neutrinos (produced through the decay of W boson in a particle collider) is short enough to cause a sufficiently long lifetime for the particles, thus ensuring an observable displacement in the LHC between the production and decay vertices. We comment on the fact that these displaced vertex signatures thus can serve as a means to verify the existence of these right-handed neutrinos in future experiments. Lastly, we line up the possibility of our future work where the vertex signatures of particles greater than the mass of W boson can be worked upon.

   hep-phInt.J.Mod.Phys.A(2022)·0 citations
6. 06*

   Final-state interaction in the process $e^{+}{e}^{-}\to {\Lambda }_c{\bar{\Lambda }}_c$

   A.I. Milstein🇷🇺 · S.G. Salnikov🇷🇺

   We show that the final-state interaction explains the nontrivial near-threshold energy dependence of the cross section of the process $e^{+}{e}^{-}\to {\Lambda }_c{\bar{\Lambda }}_c$ observed by the Belle and BESIII collaborations. This energy dependence is the result of the mixture of $S$-wave and $D$-wave components of the ${\Lambda }_c{\bar{\Lambda }}_c$ wave function due to a tensor interaction. The Coulomb potential is important only in the narrow energy region about a few MeV above the threshold of the process. It is shown that the widely used assumption that the impact of the Coulomb interaction on the cross sections of hadron production is reduced to the Sommerfeld-Gamow-Sakharov factor is not correct.

   hep-phhep-exnucl-thPRD(2022)·15 citations
7. 07*

   Data-based analysis of Forward-Backward Asymmetry in $B^{\pm }\to K^{\pm }{K}^{\mp }{K}^{\pm }$

   Rui Hu🇨🇳 · Zhen-Hua Zhang🇨🇳

   An analysis of the Forward-Backward Asymmetry (FBA) in the decay $B^{\pm }\to K^{\pm }{K}^{\mp }{K}^{\pm }$ is carried out based on the LHCb data. It is found that the large FBA observed for the invariant mass of the $K^{+}{K}^{-}$ pair around 1.5 GeV can be explained by the interference of the amplitudes between the resonances with even and odd spins, where the former can be the spin-0 $f_0(1500)$ resonance plus a non-resonance $s$-wave, while the latter is a spin-1 resonance which is probably ${\rho }^0(1450)$. The analysis shows the existence of the decay channel $B^{\pm }\to {\rho }^0(1450)K^{\pm }$, with $CP$ asymmetry of $A_{CP}(B^{\pm }\to {\rho }^0(1450)K^{\pm })=(-3.4\pm 3.0)\%$. This is in contradiction with the conclusion of BaBar in Phys. Rev. D 85, 112010, according to which the analysis showed no signal of the spin-1 resonance ${\rho }^0(1450)$. We suggest our experimental colleagues to perform a closer analysis to this channel. We also suggest to perform the measurements of the FBAs (as well as the FB-$CP$As) in other three-body decay channels of beauty and charmed mesons, as it is helpful for resonance analysis.

   hep-phhep-exPRD(2022)·9 citations
8. 08*

   Two-loop non-planar hexa-box integrals with one massive leg

   Adam Kardos🇭🇺 · Costas G. Papadopoulos🇬🇷 · Alexander V. Smirnov🇷🇺 · Nikolaos Syrrakos🇬🇷 · Christopher Wever🇩🇪

   Based on the Simplified Differential Equations approach, we present results for the two-loop non-planar hexa-box families of master integrals. We introduce a new approach to obtain the boundary terms and establish a one-dimensional integral representation of the master integrals in terms of Generalised Polylogarithms, when the alphabet contains non-factorisable square roots. The results are relevant to the study of NNLO QCD corrections for $W,Z$ and Higgs-boson production in association with two hadronic jets.

   hep-phhep-thJHEP(2022)·40 citations
9. 09*

   Mass behavior of hidden-charm pentaquarks with open-strange inspired by these established $P_c$ molecular states

   Rui Chen🇨🇳 · Xiang Liu🇨🇳

   Stimulated by the meson-baryon molecular interpretations of the $P_c$ states ($P_c(4312)/P_c(4440)/P_c(4457)$), we systematically study the interactions between an $S-$wave charm-strange baryon ${\Xi }_c^{(\prime ,\ast )}$ and an anti-charmed meson ${\bar{D}}^{(\ast )}$ in a coupled channel analysis. Effective potentials for the ${\Xi }_c^{(\prime ,\ast )}{\bar{D}}^{(\ast )}$ interactions in a one-boson-exchange model can be related to those in the ${\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}$ systems by using the $SU(3)$ flavor symmetry and heavy quark symmetry. Our results can predict several promising hidden-charm molecular pentaquarks with strangeness $|S|=1$, which include the ${\Xi }_c^{\prime }\bar{D}$ states with $I(J^P)=0,1(1/2^{-})$, the ${\Xi }_c^{\ast }\bar{D}$ states with $0,1(3/2^{-})$, the ${\Xi }_c^{\prime }{\bar{D}}^{\ast }$ states with $0(1/2^{-})$ and $0,1(3/2^{-})$, and the ${\Xi }_c^{\ast }{\bar{D}}^{\ast }$ states with $0(1/2^{-},3/2^{-},5/2^{-})$.

   hep-phPRD(2022)·33 citations
10. 10*

    Planck Formula for the Gluon Parton Distribution in the Proton

    Loredana Bellantuono🇮🇹 · Roberto Bellotti🇮🇹 · Franco Buccella🇮🇹

    We describe the gluon parton distribution function (PDF) in the proton, deduced by data from the ATLAS and HERA experiments, in the framework of the parton statistical model. The best fit parameters involved in the Planck formula that describes the gluon distribution are consistent with the results obtained from analysis of deep inelastic scattering processes. Remarkably, the agreement between the statistical model and the experimental gluon distributions is found with the same value of the "temperature" parameter $\bar{x}$ found by fitting the valence parton distributions from deep inelastic scattering. This result corroborates the validity of the statistical approach in the gluon sector.

    hep-phnucl-thMod.Phys.Lett.A(2023)·7 citations
11. 11*

    Foundations and Applications of Quantum Kinetic Theory

    Yoshimasa Hidaka🇯🇵 · Shi Pu🇨🇳 · Qun Wang🇨🇳 · Di-Lun Yang🇹🇼

    Many novel quantum phenomena emerge in non-equilibrium relativistic quantum matter under extreme conditions such as strong magnetic fields and rotations. The quantum kinetic theory based on Wigner functions in quantum field theory provides a powerful and effective microscopic description of these quantum phenomena. In this article we review some of recent advances in the quantum kinetic theory and its applications in describing these quantum phenomena.

    hep-phhep-thnucl-thPPNP(2022)·108 citations
12. 12*

    Fermion mass hierarchies from vector-like families and possible explanations for the electron and muon anomalous magnetic moments

    Huchan Lee🇬🇧

    This thesis covers a few successes of the SM and its limitations. The limitations implement that the SM must be expanded to explain the observables which can not be addressed by the SM such as mass of neutrinos, a few of anomalies, DM, DE, etc. In order to extend the SM, we take the model-dependent approach and a minimal extension to the SM. For the minimal extension, we make use of vector-like family, SM-like scalar (plus a singlet flavon), and $U(1{)}^{\prime }$ symmetry. A first BSM model in my first work is to explain both the electron and muon anomalous magnetic moments at the same time, while keeping the constraints $\mu \to e\gamma$ decay and neutrino trident production. Especially, two mass sources, chirality flip and vector-like mass, appear in our analytic prediction for the anomalies and the chirality flip mass between $0$ and $200\mathrm{GeV}$ is searched and then we show no any value between them can satisfy the anomalies at the same time. A second BSM model in my second work shares the same motivation, to explain both anomalies, however it goes one step further by considering the strong hierarchical structure of the SM into the second BSM model. In this BSM model, the SM appears as an effective theory spontaneously broken from the $U(1{)}^{\prime }$ symmetry. Both anomalies are studied in the neutrino sector first and it reveals that the neutrino contributions are too small to explain their experimental bounds, so leading to a conclusion that the neutrinos can not explain both anomalies simultaneously. Next we study the scalar contribution and show that the scalar contributions can explain both anomalies simultaneously. My third work investigate the diverse FCNCs within the same second BSM model to constrain mass range of vector-like fermions.

    hep-ph0 citations
13. 13*

    Quarkonium Suppression in the Open Quantum System Approach

    Xiaojun Yao🇺🇸

    Quarkonium suppression in relativistic heavy ion collisions has been studied experimentally for decades to probe the properties of the quark-gluon plasma. For this purpose, complete theoretical understanding of the time evolution of quarkonium inside the quark-gluon plasma is needed but challenging. Here I review recent progress in applying the open quantum system framework to describe the real-time dynamics of quarkonium, with a focus on the gauge-invariant chromoelectric field correlators of the plasma that control the dynamics.

    hep-phnucl-thRev.Mex.Fis.Suppl.(2022)·4 citations
14. 14*

    Angular asymmetries in $B\to \Lambda \bar{p}M$ decays

    Xiaotao Huang🇨🇳 · Yu-Kuo Hsiao🇨🇳 · Jike Wang🇨🇳 · Liang Sun🇨🇳

    The forward-backward angular asymmetry (${\mathcal{A}}_{FB}$) for ${\bar{B}}^0\to \Lambda \bar{p}{\pi }^{+}$ measured by Belle has presented an experimental value in the range of $-30\%$ to $-50\%$. In our study, we find that ${\mathcal{A}}_{FB}[{\bar{B}}^0\to \Lambda \bar{p}{\pi }^{+}(B^{-}\to \Lambda \bar{p}{\pi }^0)]$ can be as large as $(-14.6_{-1.5}^{+0.9}\pm 6.9)\%$. In addition, we present ${\mathcal{A}}_{FB}[{\bar{B}}^0\to \Lambda \bar{p}{\rho }^{+}(B^{-}\to \Lambda \bar{p}{\rho }^0)]=(4.1_{-0.7}^{+2.8}\pm 2.0)\%$ as the first prediction involving a vector meson in the charmless $B\to \mathbf{B}{\bar{\mathbf{B}}}^{\prime }M$ decays. While ${\mathcal{A}}_{FB}(B\to \Lambda \bar{p}M)$ indicates an angular correlation caused by the rarely studied baryonic form factors in the timelike region, LHCb and Belle~II are capable of performing experimental examinations.

    hep-phhep-exPRD(2022)·4 citations
15. 15*

    Analyzing N-point Energy Correlators Inside Jets with CMS Open Data

    Patrick T. Komiske🇺🇸 · Ian Moult🇺🇸 · Jesse Thaler🇺🇸 · Hua Xing Zhu🇨🇳

    Jets of hadrons produced at high-energy colliders provide experimental access to the dynamics of asymptotically free quarks and gluons and their confinement into hadrons. In this paper, we show that the high energies of the Large Hadron Collider (LHC), together with the exceptional resolution of its detectors, allow multipoint correlation functions of energy flow operators to be directly measured within jets for the first time. Using Open Data from the CMS experiment, we show that reformulating jet substructure in terms of these correlators provides new ways of probing the dynamics of QCD jets, which enables direct imaging of the confining transition to free hadrons as well as precision measurements of the scaling properties and interactions of quarks and gluons. This opens a new era in our understanding of jet substructure and illustrates the immense unexploited potential of high-quality LHC data sets for elucidating the dynamics of QCD.

    hep-phhep-exnucl-exnucl-thPRL(2023)·180 citations
16. 16*

    New Physics Searches at Kaon and Hyperon Factories

    Evgueni Goudzovski🇬🇧 · Diego Redigolo🇨🇭 · Kohsaku Tobioka🇺🇸 · Jure Zupan🇺🇸 · Gonzalo Alonso-Alvarez🇨🇦 · Daniele S. M. Alves🇺🇸 · Saurabh Bansal🇺🇸 · Martin Bauer🇬🇧 · Joachim Brod🇺🇸 · Veronika Chobanova🇪🇸 · Giancarlo D'Ambrosio🇮🇹 · Alakabha Datta🇺🇸 and 52 other authors

    Rare meson decays are among the most sensitive probes of both heavy and light new physics. Among them, new physics searches using kaons benefit from their small total decay widths and the availability of very large datasets. On the other hand, useful complementary information is provided by hyperon decay measurements. We summarize the relevant phenomenological models and the status of the searches in a comprehensive list of kaon and hyperon decay channels. We identify new search strategies for under-explored signatures, and demonstrate that the improved sensitivities from current and next-generation experiments could lead to a qualitative leap in the exploration of light dark sectors.

    hep-phRept.Prog.Phys.(2023)·177 citations
17. 17*

    Boosted tau lepton as a microscope and macroscope

    Sitian Qian🇨🇳 · Zhe Guan🇨🇳 · Sen Deng🇨🇳 · Yunxuan Song🇨🇳 · Tianyu Mu🇨🇳 · Jie Xiao🇨🇳 · Tianyi Yang🇨🇳 · Siguang Wang🇨🇳 · Yajun Mao🇨🇳 · Qiang Li🇨🇳 · Meng Lu🇨🇳 · Zhengyun You🇨🇳

    Anomalies from the LHCb lepton flavour universality and Fermilab muon anomalous magnetic momentum, show tantalizing hints of possible new physics from the lepton sectors. Due to its large mass and shorter lifetime than muon, the tau lepton is believed to couple more to possible new physics beyond the standard model. Traditionally, tau leptons are probed through the decay products due to tau's short life time. On the other hand, at a high energy scale, a large fraction of tau leptons could be boosted to a much longer life time and fly a visible distance from several centimetres up to kilometer length scale, yet very informative to new physics beyond the standard model or high energy cosmic rays. In this article, we show unique yet promising tau physics by exploiting long-lived taus as a microscope or macroscope, to measure tau's anomalous magnetic momentum to an unprecedented level of accuracy and detect high energy cosmic neutrinos at the 1 TeV to 1 PeV scale, respectively.

    hep-phastro-ph.HEhep-exAdv.High Energy Phys.(2022)·1 citation
18. 18*

    Why should we search for vector-like leptons?

    Feyza Baspehlivan🇹🇷 · Burak Dagli🇹🇷 · Osman Emre Delialioglu🇹🇷 · Saleh Sultansoy🇹🇷

    There are two strong arguments in favor of vector-like leptons and quarks: Flavor Democracy call for them, and E6 GUT predicts existence of iso-singlet quarks and iso-doublet leptons. Vector-like quarks (VLQ) are extensively searched by ATLAS and CMS collaborations, but this is not the case for vector-like leptons (VLL), while they have actually similar status from phenomenology viewpoint. In this study we argue that vector-like leptons should be included into the new physics search programs of energy-frontier colliders. We consider production of vector-like partners of the first SM family leptons at the HL-LHC, HE-LHC, FCC, ILC, CLIC, Muon Collider, as well as, at ep and {\mu}-p colliders. As for decays of vector-like leptons, we present branching ratios formulas to different channels for the most general case. Since there are many different production and decay channels for charged and neutral vector-like leptons, relevant studies should be done systematically. We invite the High Energy Physics community (both experimenters and phenomenologists) to actively participate in research on this topic.

    hep-phhep-ex12 citations
19. 19*

    Gravitational entropy and the flatness, homogeneity and isotropy puzzles

    Neil Turok🇨🇦 · Latham Boyle🇨🇦

    We suggest a new explanation for the observed large scale flatness, homogeneity and isotropy of the universe. The basic ingredients are elementary and well-known, namely Einstein's theory of gravity and Hawking's method of computing gravitational entropy. The new twist is provided by the boundary conditions we recently proposed for "big bang" type singularities dominated by conformal matter, enforcing $CPT$ symmetry and analyticity. Here, we show that, besides allowing us to describe the big bang, these boundary conditions allow new gravitational instantons, enabling us to calculate the gravitational entropy of cosmologies which include radiation, dark energy and space curvature of either sign. We find the gravitational entropy of these universes, $S_g\sim S_{\Lambda }^{1/4}{S}_r$, where $S_{\Lambda }$ is the famous de Sitter entropy and $S_r$ is the total entropy in radiation. To the extent that $S_g$ exceeds $S_{\Lambda }$, the most probable universe is flat. By analysing the perturbations about our new instantons, we argue it is also homogeneous and isotropic on large scales.

    ↳ hep-thastro-ph.COgr-qchep-phPLB(2024)·26 citations
20. 20*

    Efficient emulation of relativistic heavy ion collisions with transfer learning

    Dananjaya Liyanage🇺🇸 · Yi Ji🇺🇸 · Derek Everett🇺🇸 · Matthew Heffernan🇨🇦 · Ulrich Heinz🇺🇸 · Simon Mak🇺🇸 · Jean-Francois Paquet🇺🇸

    Measurements from the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC) can be used to study the properties of quark-gluon plasma. Systematic constraints on these properties must combine measurements from different collision systems and methodically account for experimental and theoretical uncertainties. Such studies require a vast number of costly numerical simulations. While computationally inexpensive surrogate models ("emulators") can be used to efficiently approximate the predictions of heavy ion simulations across a broad range of model parameters, training a reliable emulator remains a computationally expensive task. We use transfer learning to map the parameter dependencies of one model emulator onto another, leveraging similarities between different simulations of heavy ion collisions. By limiting the need for large numbers of simulations to only one of the emulators, this technique reduces the numerical cost of comprehensive uncertainty quantification when studying multiple collision systems and exploring different models.

    ↳ nucl-thhep-phPRC(2022)·25 citations
21. 21*

    Quantum Scale Invariant Gravity with de Donder Gauge

    Ichiro Oda🇯🇵

    We perform the manifestly covariant quantization of a scale invariant gravity with a scalar field, which is equivalent to the well-known Brans-Dicke gravity via a field redefinition of the scalar field, in the de Donder gauge condition (or harmonic gauge condition) for general coordinate invariance. First, without specifying the expression of a gravitational theory, we write down various equal-time (anti-)commutation relations (ETCRs), in particular, those involving the Nakanishi-Lautrup field, the FP ghost, and the FP antighost only on the basis of the de Donder gauge condition. It is shown that choral symmetry, which is a Poincar$\acute{\mathrm{e}}$-like $IOSp(8|8)$ supersymmetry, can be derived from such a general action with the de Donder gauge. Next, taking the scale invariant gravity with a scalar field as a classical theory, we derive the ETCRs for the gravitational sector involving the metric tensor and scalar fields. Moreover, we account for how scale symmetry is spontaneously broken in quantum gravity, thereby showing that the dilaton is a massless Nambu-Goldstone particle.

    ↳ hep-thgr-qchep-phPRD(2022)·17 citations
22. 22*

    Einstein Gauss-Bonnet Theories as Ordinary, Wess-Zumino Conformal Anomaly Actions

    Claudio Corianò🇮🇹 · Matteo Maria Maglio🇩🇪

    Recently, the possibility of evading Lovelock's theorem at $d=4$, via a singular redefinition of the dimensionless coupling of the Gauss-Bonnet term, has been very extensively discussed in the cosmological context. The term is added as a quadratic contribution of the curvature tensor to the Einstein-Hilbert action, originating theories of "Einstein Gauss-Bonnet" (EGB) type. We point out that the action obtained by the dimensional regularization procedure, implemented with the extraction of a single conformal factor, correspond just to an ordinary Wess-Zumino anomaly action, even though it is deprived of the contribution from the Weyl tensor. We also show that a purely gravitational version of the EGB theory can be generated by allowing a finite renormalization of the Gauss-Bonnet topological contribution at $d=4+ϵ$, as pointed out by Mazur and Mottola. The result is an effective action which is quadratic, rather then quartic, in the dilaton field, and scale free, compared to the previous derivations. The dilaton, in this case can be removed from the spectrum, leaving a pure gravitational theory, which is nonlocal. We comment on the physical meaning of the two types of actions, which may be used to describe such topological terms both below and above the conformal breaking scale.

    ↳ hep-thgr-qchep-phPLB(2022)·8 citations
23. 23*

    S-wave pion condensation in symmetric nuclear matter

    D. N. Voskresensky (JINR, Dubna, Russia)🇷🇺

    S-wave pion-nucleon interactions in the linear sigma model, and in Manohar-Georgi and Gasser-Sainio-Svarc models with finite number of terms in Lagrangians, as well as in a general phenomenological approach are reviewed. Subtleties associated with the current algebra theorems and field redefinitions are discussed. In the first and third models most likely the s-wave pion condensation in the isospin-symmetric matter does not occur at least up to high densities, whereas within the second model it may appear already at moderate densities. In the phenomenological approach two parameterizations of the s-wave pion-nucleon scattering amplitude and the pion polarization operator used in the literature are considered. The first parameterization employs the off-mass-shell amplitude and allows to fulfil the current algebra theorems. Using it the s-wave pion polarization operator in the isospin-symmetric matter is reconstructed within the gas approximation. With this pion polarization operator the s-wave pion condensation in the isospin-symmetric matter does not occur at least up to high densities. Second parameterization uses the on-mass-shell pion-nucleon scattering amplitude and does not satisfy the Adler and Weinberg conditions. With such a parameterization most likely the s-wave pion condensation in the isospin-symmetric matter may occur already at the nucleon density $n\simeq (1.4-2.5)n_0$, where $n_0$ is the density of the atomic nucleus, that should result in observable effects. Both parameterizations allow to successfully describe the pion atom data.

    ↳ nucl-thhep-phPRD(2022)·12 citations
24. 24*

    Cold Atoms in Space: Community Workshop Summary and Proposed Road-Map

    Ivan Alonso · Cristiano Alpigiani · Brett Altschul · Henrique Araujo · Gianluigi Arduini · Jan Arlt · Leonardo Badurina · Antun Balaz · Satvika Bandarupally · Barry C Barish Michele Barone · Michele Barsanti · Steven Bass and 237 other authors

    We summarize the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with ESA and national space and research funding agencies.

    ↳ astro-ph.IMgr-qchep-exhep-ph+1EPJ Quant.Technol.(2022)·63 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.