Mon·Mar 7, 2022Monday·March 7, 2022

1. 01*

   Null test BSM searches with rare charm baryon decays

   Marcel Golz🇩🇪 · Gudrun Hiller🇩🇪 · Tom Magorsch🇩🇪

   Rare $|\Delta c|=|\Delta u|=1$ processes uniquely probe flavor in the Standard Model and beyond from the up-type quark sector. Opportunities to search for BSM physics in charm arise from the severe GIM suppression which kills SM contributions to leptonic axial-vector contributions and suppresses CP violation. Semileptonic decays of charmed hadrons offer a variety of clean null test observables, featuring new physics effects which are even enhanced by resonance contributions. In particular, angular observables in three- and self-analyzing four-body baryon decays, such as ${\Lambda }_c\to p{\ell }^{+}{\ell }^{-}$ and ${\Xi }_c^{+}\to {\Sigma }^{+}(\to p{\pi }^0){\ell }^{+}{\ell }^{-}$, ${\Xi }_c^0\to {\Lambda }^0(\to p{\pi }^{-}){\ell }^{+}{\ell }^{-}$ and ${\Omega }_c^0\to {\Xi }^0(\to {\Lambda }^0{\pi }^0){\ell }^{+}{\ell }^{-}$ disentangle possible new physics effects in electromagnetic dipole couplings $C_7^{(\prime )}$ and (axial-)vector 4-fermion ones $C_{9(10)}^{(\prime )}$. There is sensitivity to BSM couplings as small as $\sim 0.01$.

   hep-phhep-exPoS(2023)·2 citations
2. 02*

   Gravitational Portals with Non-Minimal Couplings

   Simon Clery🇫🇷 · Yann Mambrini🇫🇷 · Keith A. Olive🇺🇸 · Andrey Shkerin🇺🇸 · Sarunas Verner🇺🇸

   We consider the effects of non-minimal couplings to curvature of the form ${\xi }_S{S}^{2}R$, for three types of scalars: the Higgs boson, the inflaton, and a scalar dark matter candidate. We compute the abundance of dark matter produced by these non-minimal couplings to gravity and compare to similar results with minimal couplings. We also compute the contribution to the radiation bath during reheating. The main effect is a potential augmentation of the maximum temperature during reheating. A model independent limit of $\mathcal{O}(10^{12})$ GeV is obtained. For couplings ${\xi }_S\gtrsim \mathcal{O}(1)$, these dominate over minimal gravitational interactions.

   hep-phastro-ph.COhep-thPRD(2022)·90 citations
3. 03*

   Color Transparency and Light Front Holographic QCD

   Gerald A. Miller🇺🇸

   Color transparency, the reduction of initial- or final-state interactions in coherent nuclear processes, is a natural prediction of QCD provided that small-sized or point-like configurations (PLCs) are responsible for high-momentum transfer, high-energy, semi-exclusive processes. I use the FMS criteria for the existence of PLCs to show that the wave functions of light front holographic QCD, as currently formulated, do not contain a PLC.

   hep-phnucl-exnucl-thMDPI Physics(2022)·3 citations
4. 04*

   Dispersive analysis of the $\pi \pi$ and $\pi K$ scattering data

   Oleksandra Deineka🇩🇪 · Igor Danilkin🇩🇪 · Marc Vanderhaeghen🇩🇪

   We present a data-driven analysis of the S-wave $\pi \pi \to \pi \pi (I=0,2)$ and $\pi K\to \pi K(I=1/2,3/2)$ reactions using the partial-wave dispersion relation. The contributions from the left-hand cuts are parametrized using the expansion in a suitably constructed conformal variable, which accounts for its analytical structure. The partial-wave dispersion relation is solved numerically using the $N/D$ method. The fits to the experimental data supplemented with the constraints from chiral perturbation theory at threshold and Adler zero give the results consistent with Roy-like (Roy-Steiner) analyses. For the $\pi \pi$ scattering we present the coupled-channel analysis by including additionally the $K\bar{K}$ channel. By the analytic continuation to the complex plane, we found poles associated with the lightest scalar resonances $\sigma /f_0(500)$, $f_0(980)$, and $\kappa /K_0^{\ast }(700)$. For all the channels we also performed the fits directly to the Roy-like (Roy-Steiner) solutions in the physical region, in order to minimize the $N/D$ uncertainties in the complex plane and to extract the most constrained Omnès functions.

   hep-phPoS(2024)·5 citations
5. 05*

   Factorizing Hidden Particle Production Rates

   Philipp Klose🇨🇭

   A method is proposed to streamline the computation of hidden particle production rates by factorizing them into i) a model-independent SM contribution, and ii) a observable-independent hidden sector contribution. The Standard Model (SM) contribution can be computed once for each observable and re-used for a wide array of hidden sector models, while the hidden sector contribution can be computed once for each model, and re-used for a wide array of observables. The SM contribution also facilitates extracting model independent constraints on hidden particle production. The method is compatible with effective field theory (EFT) and simplified model approaches. It is illustrated by factorizing the rate of charged kaon decays into a charged lepton and a number of hidden particles, and a single form factor $F_{\ell }$ is found to parametrize the impact of general hidden sectors. We derive model-independent constraints on the form factor $F_e$ that governs decays into positrons and hidden particles.

   hep-phhep-thJHEP(2022)·2 citations
6. 06*

   A Simplified Twin Pati-Salam Theory of Flavour with a TeV Scale Vector Leptoquark

   Stephen F. King🇬🇧

   In this talk, we discuss a simplified version of a recently proposed twin Pati-Salam (PS) theory of flavour broken to the $G_{4321}$ gauge group at high energies, then to the Standard Model at low energies, yielding a TeV scale vector leptoquark $U_1^{\mu }(3,1,2/3)$ which may be used to address the lepton universality anomalies $R_{K^{(\ast )}}$ and $R_{D^{(\ast )}}$ in $B$ decays. The model also accounts for quark and lepton mass hierarchies, providing a link between the flavour anomalies and a theory of flavour.

   hep-phPoS(2022)·2 citations
7. 07*

   Stability analysis of non-thermal fixed points in longitudinally expanding kinetic theory

   Aleksandr N. Mikheev🇩🇪 · Aleksas Mazeliauskas🇨🇭 · Jürgen Berges🇩🇪

   We use the Hamiltonian formulation of kinetic theory to perform a stability analysis of non-thermal fixed points in a non-Abelian plasma. We construct a perturbative expansion of the Fokker-Planck collision kernel in an adiabatic approximation and show that the (next-to-)leading order solutions reproduce the known non-thermal fixed point scaling exponents. Working at next-to-leading order, we derive the stability equations for scaling exponents and find the relaxation rate to the non-thermal fixed point. This approach provides the basis for an understanding of the prescaling phenomena observed in QCD kinetic theory and non-relativistic Bose gas systems.

   hep-phcond-mat.quant-gasnucl-thPRD(2022)·15 citations
8. 08*

   Composite nature of $Z_b$ states from data analysis

   Lu Zhang🇨🇳 · Xian-Wei Kang🇨🇳 · Xin-Heng Guo🇨🇳

   We use a near-threshold parameterization with explicit inclusion of the Castillejo-Dalitz-Dyson poles, which is more general than the effective range expansion, to study the bottomonium-like states $Z_b(10610)$ and $Z_b(10650)$. In terms of the partial-wave amplitude, we fit the event number distribution of $B^{(\ast )}{\bar{B}}^{\ast }$ system to the experimental data for these resonances from Belle Collaboration. The data could be described very well in our method, which supports the molecular interpretation. Then the relevant physical quantities are obtained, including the $B^{(\ast )}{\bar{B}}^{\ast }$ scattering length ($a$), effective range ($r$), and residue squared (${\gamma }_s^2$) of the pole in the complex plane. In particular, we find the compositeness can range from about 0.4 up to 1 for the $B{\bar{B}}^{\ast }$ ($B^{\ast }{\bar{B}}^{\ast }$) component in the resonance $Z_b(10610)$ ($Z_b(10650)$).

   hep-phhep-exnucl-thEPJC(2022)·9 citations
9. 09*

   Bottom Quark Mass with Calibrated Uncertainty

   Jens Erler🇩🇪 · Pere Masjuan🇪🇸 · Hubert Spiesberger🇩🇪

   We determine the bottom quark mass ${\hat{m}}_b$ from QCD sum rules of moments of the vector current correlator calculated in perturbative QCD to $\mathcal{O}({\hat{\alpha }}_s^3)$. Our approach is based on the mutual consistency across a set of moments where experimental data are required for the resonance contributions only. Additional experimental information from the continuum region can then be used for stability tests and to assess the theoretical uncertainty. We find ${\hat{m}}_b({\hat{m}}_b)=(4180.2\pm 7.9)$ MeV for ${\hat{\alpha }}_s(M_Z)=0.1182$.

   hep-phEPJC(2022)·8 citations
10. 10*

    Search for the anomalous $ZZ\gamma$ and $Z\gamma \gamma$ couplings via $\nu \nu \gamma$ production at the CLIC

    S. Spor🇹🇷 · E. Gurkanli🇹🇷 · M. Köksal🇹🇷

    The non-Abelian gauge structure of the Standard Model implies the presence of the multi-boson self-interactions. Precise measurements in experimental and theoretical studies of these interactions allow not only testing the nature of the Standard Model but also new physics contribution coming from the beyond Standard Model. These interactions can be examined using a model-independent way in effective theory approach that composes the motivation part of this study. In this paper, we examine the anomalous $ZZ\gamma$ and $Z\gamma \gamma$ neutral triple gauge couplings via the process $e^{-}{e}^{+}\to Z\gamma$ for the neutrino-antineutrino pair decay of $Z$ boson. It has performed with both unpolarized and polarized electron beams at the Compact Linear Collider with $\sqrt{s}=3$ TeV. The study focused on $CP$-conserving $C_{\tilde{B}W}/{\Lambda }^4$ and $CP$-violating $C_{BB}/{\Lambda }^4$, $C_{BW}/{\Lambda }^4$, $C_{WW}/{\Lambda }^4$ couplings. Obtained sensitivities on the anomalous neutral triple gauge couplings with $95\%$ Confidence Level are given with systematic uncertainties of $0\%$, $5\%$ and $10\%$ for unpolarized, $-80\%$ and $80\%$ polarized electron beams with integrated luminosities of ${\mathcal{L}}_{\text{int}}=5$ $\mathrm{a}{\mathrm{b}}^{-1}$, ${\mathcal{L}}_{\text{int}}=4$ $\mathrm{a}{\mathrm{b}}^{-1}$ and ${\mathcal{L}}_{\text{int}}=1$ $\mathrm{a}{\mathrm{b}}^{-1}$, respectively. Comparing the latest experimental limits and related phenomenological studies, our results on the anomalous neutral gauge couplings are set more stringent sensitivity between 10-30 times of magnitude.

    hep-phNPB(2022)·14 citations
11. 11*

    Contribution of the non-resonant mechanism to the double and single differential distributions over the invariant variables in the reaction $e^{+}+e^{-}\to N+\bar{N}+{\pi }^0$

    G. I. Gakh🇺🇦 · M.I. Konchatnij🇺🇦 · N.P. Merenkov🇺🇦 · E. Tomasi-Gustafsson🇫🇷

    The general analysis of the differential cross section and various polarization observables is performed for the process $e^{+}+e^{-}\to N+\bar{N}+{\pi }^0$ assuming that the annihilation occurs through the exchange of one virtual photon. The dependence of the differential distributions over invariant variables is derived for the reaction $e^{+}+e^{-}\to N+\bar{N}+{\pi }^0$ in the so-called non-resonant mechanism, applying the conservation of the hadron electromagnetic currents and the P-invariance of the hadron electromagnetic interaction. The detection in an exclusive experimental set up where the nucleon (or antinucleon) and pion are detected in coincidence is considered. A number of single and double differential distributions have been calculated analytically and numerical estimates are given for the $p\bar{p}{\pi }^0$ and $n\bar{n}{\pi }^0$ channels, in the Born (non-resonant) approximation, in the energy range from threshold up to $s=16$ GeV${}^2$.

    hep-phnucl-thPRD(2022)·3 citations
12. 12*

    Consequences of the Dresden-II reactor data for the weak mixing angle and new physics

    D. Aristizabal Sierra🇨🇱 · V. De Romeri🇪🇸 · D. K. Papoulias🇬🇷

    The Dresden-II reactor experiment has recently reported a suggestive evidence for the observation of coherent elastic neutrino-nucleus scattering, using a germanium detector. Given the low recoil energy threshold, these data are particularly interesting for a low-energy determination of the weak mixing angle and for the study of new physics leading to spectral distortions at low momentum transfer. Using two hypotheses for the quenching factor, we study the impact of the data on: (i) The weak mixing angle at a renormalization scale of $\sim 10\text{MeV}$, (ii) neutrino generalized interactions with light mediators, (iii) the sterile neutrino dipole portal. The results for the weak mixing angle show a strong dependence on the quenching factor choice. Although still with large uncertainties, the Dresden-II data provide for the first time a determination of ${\sin }^2{\theta }_W$ at such scale using coherent elastic neutrino-nucleus scattering data. Tight upper limits are placed on the light vector, scalar and tensor mediator scenarios. Kinematic constraints implied by the reactor anti-neutrino flux and the ionization energy threshold allow the sterile neutrino dipole portal to produce up-scattering events with sterile neutrino masses up to $\sim 8$MeV. In this context, we find that limits are also sensitive to the quenching factor choice, but in both cases competitive with those derived from XENON1T data and more stringent that those derived with COHERENT data, in the same sterile neutrino mass range.

    hep-phhep-exnucl-exnucl-thJHEP(2022)·48 citations
13. 13*

    Off-shell Higgs Interpretations Task Force: Models and Effective Field Theories Subgroup Report

    Aleksandr Azatov🇮🇹 · Jorge de Blas🇪🇸 · Adam Falkowski🇫🇷 · Andrei V. Gritsan🇺🇸 · Christophe Grojean🇩🇪 · Lucas Kang🇺🇸 · Nikolas Kauer🇬🇧 · Ennio Salvioni🇮🇹 · Ulascan Sarica🇺🇸 · Marion Thomas🇬🇧 · Eleni Vryonidou🇬🇧

    This report presents the results of the Models and Effective Field Theories Subgroup of the Off-Shell Interpretations Task Force in the LHC Higgs Working Group. The main goal of the subgroup was to discuss and advance the potential impact of off-shell Higgs measurements on searches for BSM physics carried out in the EFT framework or as benchmark model studies. In the first contribution, the off-shell potential to resolve flat directions in parameter space for on-shell measurements is studied. Furthermore, the sensitivity of off-shell measurements to SMEFT dimension-6 operators for the gg $\to$ ZZ process is discussed, and studies of explicit models that are testable in off-shell production are reviewed. In the second contribution, the SMEFT effects in the off-shell gluon fusion and electroweak processes are discussed. Subsequently, the computation of integrated and differential effects using SMEFT@NLO and MG5_aMC@NLO, or JHUGen and MCFM, is demonstrated. On that basis, a study of the prospects of obtaining additional SMEFT constraints - beyond those from existing global fits - by utilising the off-shell process is presented. For clarification, a revised introduction, definition and discussion of the Higgs basis parametrisation of the SMEFT is given in the third contribution. In short notes on the SMEFT, the Higgs basis with an additional constraint is discussed and relations between the Higgs and Warsaw bases are presented. Lastly, an overview of EFT calculations and tools is given.

    hep-phhep-ex29 citations
14. 14*

    Scaling and adiabaticity in a rapidly expanding gluon plasma

    Jasmine Brewer🇨🇭 · Bruno Scheihing-Hitschfeld🇺🇸 · Yi Yin🇨🇳

    In this work we aim to gain qualitative insight on the far-from-equilibrium behavior of the gluon plasma produced in the early stages of a heavy-ion collision. It was recently discovered arXiv:1810.10554 that the distribution functions of quarks and gluons in QCD effective kinetic theory (EKT) exhibit self-similar "scaling" evolution with time-dependent scaling exponents long before those exponents reach their pre-hydrodynamic fixed-point values. In this work we shed light on the origin of this time-dependent scaling phenomenon in the small-angle approximation to the Boltzmann equation. We first solve the Boltzmann equation numerically and find that time-dependent scaling is a feature of this kinetic theory, and that it captures key qualitative features of the scaling of hard gluons in QCD EKT. We then proceed to study scaling analytically and semi-analytically in this equation. We find that an appropriate momentum rescaling allows the scaling distribution to be identified as the instantaneous ground state of the operator describing the evolution of the distribution function, and the approach to the scaling function is described by the decay of the excited states. That is to say, there is a frame in which the system evolves adiabatically. Furthermore, from the conditions for adiabaticity we can derive evolution equations for the time-dependent scaling exponents. In addition to the known free-streaming and BMSS fixed points, we identify a new "dilute" fixed point when the number density becomes small before hydrodynamization. Corrections to the fixed point exponents in the small-angle approximation agree quantitatively with those found previously in QCD EKT and arise from the evolution of the ratio between hard and soft scales.

    hep-phhep-thnucl-thJHEP(2022)·38 citations
15. 15*

    Constraining 3-3-1 Models at the LHC and Future Hadron Colliders

    A. Alves🇧🇷 · L. Duarte🇧🇷 · S. Kovalenko🇨🇱 · Y. M. Oviedo-Torres🇧🇷 · F. S. Queiroz🇧🇷 · Y. S. Villamizar🇧🇷

    In this work, we derive lower mass bounds on the Z' gauge boson based on the dilepton data from LHC with 13 TeV of center-of-mass energy, and forecast the sensitivity of the High-Luminosity-LHC with $L=3000f{b}^{-1}$, the High-Energy LHC with $\sqrt{s}=27$ TeV, and also at the Future Circular Collider with $\sqrt{s}=100$ TeV. We take into account the presence of exotic and invisible decays of the Z' gauge boson to find a more conservative and robust limit, different from previous studies. We investigate the impact of these new decays channels for several benchmark models in the scope of two different 3-3-1 models. We found that in the most constraining cases, LHC with $139f{b}^{-1}$ can impose $m_{Z^{\prime }}>4$ TeV. Moreover, we forecast HL-LHC, HE-LHC, and FCC bounds that yield $m_{Z^{\prime }}>5.8$ TeV, $m_{Z^{\prime }}>9.9$ TeV, and $m_{Z^{\prime }}>27$ TeV, respectively. Lastly, put our findings into perspective with dark matter searches to show the region of parameter space where a dark matter candidate with the right relic density is possible.

    hep-phhep-exPRD(2022)·31 citations
16. 16*

    PIONEER: Studies of Rare Pion Decays

    PIONEER Collaboration: W. Altmannshofer · H. Binney · E. Blucher · D. Bryman · L. Caminada · S. Chen · V. Cirigliano · S. Corrodi · A. Crivellin · S. Cuen-Rochin · A. DiCanto · L. Doria and 48 other authors

    A next-generation rare pion decay experiment, PIONEER, is strongly motivated by several inconsistencies between Standard Model (SM) predictions and data pointing towards the potential violation of lepton flavor universality. It will probe non-SM explanations of these anomalies through sensitivity to quantum effects of new particles even if their masses are at very high scales. Measurement of the charged-pion branching ratio to electrons vs. muons $R_{e/\mu }$ is extremely sensitive to new physics effects. At present, the SM prediction for $R_{e/\mu }$ is known to 1 part in $10^4$, which is 15 times more precise than the current experimental result. An experiment reaching the theoretical accuracy will test lepton flavor universality at an unprecedented level, probing mass scales up to the PeV range. Measurement of pion beta decay, ${\pi }^{+}\to {\pi }^0{e}^{+}\nu (\gamma )$, with 3 to 10-fold improvement in sensitivity, will determine $V_{ud}$ in a theoretically pristine manner and test CKM unitarity, which is very important in light of the recently emerged tensions. In addition, various exotic rare decays involving sterile neutrinos and axions will be searched for with unprecedented sensitivity. The experiment design benefits from experience with the recent PIENU and PEN experiments at TRIUMF and the Paul Scherrer Institut (PSI). Excellent energy and time resolutions, greatly increased calorimeter depth, high-speed detector and electronics response, large solid angle coverage, and complete event reconstruction are all critical aspects of the approach. The PIONEER experiment design includes a 3$\pi$ sr 25 radiation length calorimeter, a segmented low gain avalanche detector stopping target, a positron tracker, and other detectors. Using intense pion beams, and state-of-the-art instrumentation and computational resources, the experiments can be performed at the PSI ring cyclotron.

    ↳ hep-exhep-phphysics.ins-det89 citations
17. 17*

    Evolution of X-ray Activity in <25 Myr Old Pre-Main Sequence Stars

    Konstantin V. Getman (1)🇺🇸 · Eric D. Feigelson (1)🇺🇸 · Gordon P. Garmire (2)🇺🇸 · Patrick S. Broos (1)🇺🇸 · Michael A. Kuhn (3)🇺🇸 · Thomas Preibisch (4)🇩🇪 · Vladimir S. Airapetian (5,6) ((1) Pennsylvania State University, (2) Huntingdon Institute for X-ray Astronomy, (3) California Institute of Technology, (4) USM, LMU, (5) American University, (6) NASA/GSFC/SEEC)🇺🇸

    Measuring the evolution of X-ray emission from pre-main sequence (PMS) stars gives insight into two issues: the response of magnetic dynamo processes to changes in interior structure and the effects of high-energy radiation on protoplanetary disks and primordial planetary atmospheres. We present a sample of 6,003 stars with ages 7-25Myr in ten nearby open clusters from Chandra X-ray and Gaia-EDR3 surveys. Combined with previous results in large samples of younger (<5Myr) stars in MYStIX and SFiNCs star forming regions, mass-stratified activity-age relations are derived for early phases of stellar evolution. X-ray luminosity (Lx) is constant during the first few Myr, possibly due to the presence of extended X-ray coronas insensitive to temporal changes in stellar size. Lx then decays during the 7-25Myr period, more rapidly as stellar mass increases. This decay is interpreted as decreasing efficiency of the alpha^2 dynamo as radiative cores grow and a solar-type alpha-Omega dynamo emerges. For more massive 3.5-7Mo fully radiative stars, the X-ray emission plummets indicating lack of an effective magnetic dynamo. The findings provide improved measurements of high energy radiation effects on circumstellar material, first the protoplanetary disk and then the atmospheres of young planets. The observed X-ray luminosities can be so high that an inner Earth-mass rocky, unmagnetized planet around a solar-mass PMS star might lose its primary and secondary atmospheres within a few-several million years. PMS X-ray emission may thus have a significant impact on evolution of early planetary atmospheres and the conditions promoting the rise of habitability.

    ↳ astro-ph.SRastro-ph.EPastro-ph.HEhep-phApJ(2022)·9 citations
18. 18*

    Thermal Relaxation of Dark Matter Admixed Neutron Star

    Ankit Kumar🇮🇳 · H. C. Das🇮🇳 · S. K. Patra🇮🇳

    Motivated by the various theoretical studies regarding the efficient capturing of dark matter by neutron stars, we explore the possible indirect effects of captured dark matter on the cooling mechanism of a neutron star. The equation of states for different configurations of dark matter admixed star at finite temperature is obtained using the relativistic mean-field formalism with the IOPB-I parameter set. We show that the variation in the dark matter momentum vastly modifies the neutrino emissivity through specific neutrino generating processes of the star. The specific heat and the thermal conductivity of a dark matter admixed star have also been investigated to explore the propagation of cooling waves in the interior of the star. The dependence of theoretical surface temperature cooling curves on the equation of state and chemical composition of the stellar matter has also been discussed along with the observational data of thermal radiation from various sources. We observed that the dark matter admixed canonical stars with $k_f^{\mathrm{DM}}>0.04$ comply with the fast cooling scenario. Further, the metric for internal thermal relaxation epoch has also been calculated with different dark matter momentum and we deduced that increment of dark matter segment amplify the cooling and internal relaxation rates of the star.

    ↳ astro-ph.HEhep-phnucl-thMNRAS(2022)·29 citations
19. 19*

    Some recent advances in the understanding of $\mathcal{N}=4$ supersymmetric Yang-Mills thermodynamics

    Ubaid Tantary🇺🇸 · Qianqian Du🇺🇸 · Michael Strickland🇺🇸

    The interest in the thermodynamics of supersymmetric Yang-Mills started after Maldacena proposed the duality between string theory on AdS backgrounds and the large-N limit of SYM theories. One of the motivations to study the thermal properties of $\mathcal{N}=4$ supersymmetric Yang-Mills in four dimensions (SYM${}_{4,4}$) is that at high temperatures, the weak-coupling limit of this theory has many similarities with high temperature quantum chromodynamics (QCD). In this proceedings contribution, we review recent calculations of the resummed perturbative free energy of $\mathcal{N}=4$ supersymmetric Yang-Mills in four spacetime dimensions through second order in the 't Hooft coupling $\lambda$ at finite temperature and zero chemical potential. We compare our final result with prior results obtained in the weak and strong-coupling limits and construct a generalized Padé approximant that interpolates between the weak-coupling result and the large-$N_c$ strong-coupling result.

    ↳ hep-thhep-phPoS(2022)·0 citations
20. 20*

    Purely Virtual Particles in Quantum Gravity, Inflationary Cosmology and Collider Physics

    Damiano Anselmi🇮🇹

    We review the concept of purely virtual particle and its uses in quantum gravity, primordial cosmology and collider physics. The fake particle, or "fakeon", which mediates interactions without appearing among the incoming and outgoing states, can be introduced by means of a new diagrammatics. The renormalization coincides with the one of the parent Euclidean diagrammatics, while unitarity follows from spectral optical identities, which can be derived by means of algebraic operations. The classical limit of a theory of physical particles and fakeons is described by an ordinary Lagrangian plus Hermitian, micro acausal and micro nonlocal self-interactions. Quantum gravity propagates the graviton, a massive scalar field (the inflaton) and a massive spin-2 fakeon, and leads to a constrained primordial cosmology, which predicts the tensor-to-scalar ratio $r$ in the window $0.4\lesssim 1000r\lesssim 3.5$. The interpretation of inflation as a cosmic RG flow allows us to calculate the perturbation spectra to high orders in the presence of the Weyl squared term. In models of new physics beyond the standard model, fakeons evade various phenomenological bounds, because they are less constrained than normal particles. The resummation of self-energies reveals that it is impossible to get too close to the fakeon peak. The related peak uncertainty, equal to the fakeon width divided by 2, is expected to be observable.

    ↳ hep-thgr-qchep-phSymmetry(2022)·2 citations
21. 21*

    The Franson experiment as an example of spontaneous breaking of time-translation symmetry

    David H. Oaknin🇮🇱

    We describe an explicit statistical model of local hidden variables that reproduces the predictions of quantum mechanics for the ideal Franson experiment and sheds light on the physical mechanisms that might be involved in the actual experiment. The crux of our model is the spontaneous breaking of the time-translation gauge symmetry by the hidden configurations of the pairs of photons locked in time and energy involved in the experiment, which acquire a non-zero geometric phase through certain cyclic transformations.

    ↳ quant-phhep-phSymmetry(2022)·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.