Fri·Sep 17, 2021Friday·September 17, 2021

1. 01*

   Light Cone Distribution Amplitudes of Heavy-Light Mesons and Quarkonia

   Fernando E. Serna🇧🇷 · Bruno El-Bennich🇧🇷

   In this work we use the framework of the Dyson-Schwinger and Bethe-Salpeter equations to compute Light-Cone Distribution Amplitudes of heavy-light mesons and quarkonia. In studying the meson properties, we introduce a flavor dependence in the heavy-quark sector of the Bethe-Salpeter ladder kernel which yields improved numerical results for masses and leptonic decay constants of the pseudoscalar $D$, $D_s$, $B$ and $B_s$ mesons. Finally, the corresponding heavy-light Bethe-Salpeter amplitudes are projected onto the light front and we reconstruct the distribution amplitudes of the mesons in the full theory.

   hep-phnucl-thPoS(2021)·6 citations
2. 02*

   Isospin-breaking corrections to ${\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau }$ decays and the muon $g-2$

   J. A. Miranda🇲🇽

   We review the isospin-breaking and electromagnetic corrections to the ${\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau }$ decays, which are used as an input to the two-pion contributions to the hadronic vacuum polarization (at LO) of the anomalous magnetic moment ($a_{\mu }$). We extend previous analyses by Cirigliano et al. working with ChPT with resonances. As an outcome, we improve the agreement between this determination and the other based on $e^{+}{e}^{-}$ data. The new results are in better agreement with an old estimation that uses Vector Dominance Model (VMD), and the discrepancy between the SM prediction and the combined results from BNL and FNAL is reduced to $2.1\sigma$ at $\mathcal{O}(p^4)$ and $2.3\sigma$ at $\mathcal{O}(p^6)$.

   hep-phPoS(2020)·1 citation
3. 03*

   Penning-Trap Searches for Lorentz and CPT Violation

   Yunhua Ding🇺🇸 · Teague D. Olewiler🇺🇸 · Mohammad Farhan Rawnak🇺🇸

   An overview of recent progress on testing Lorentz and CPT symmetry using Penning traps is presented. The theory of quantum electrodynamics with Lorentz-violating operators of mass dimensions up to six is summarized. Dominant shifts in the cyclotron and anomaly frequencies of the confined particles and antiparticles due to Lorentz and CPT violation are derived. Existing results of the comparisons of charge-to-mass ratios and magnetic moments involving protons, antiprotons, electrons, and positrons are used to constrain various coefficients for Lorentz violation.

   hep-phSymmetry(2021)·3 citations
4. 04*

   Different faces of confinement

   Roman Pasechnik🇸🇪 · Michal Šumbera🇨🇿

   In this review, we provide a short outlook of some of the currently most popular pictures and promising approaches to non-perturbative physics and confinement in gauge theories. A qualitative and by no means exhaustive discussion presented here covers such key topics as the phases of QCD matter, the order parameters for confinement, the central vortex and monopole pictures of the QCD vacuum structure, fundamental properties of the string tension, confinement realisations in gauge-Higgs and Yang-Mills theories, magnetic order/disorder phase transition among others.

   hep-phhep-lathep-thUniverse(2021)·17 citations
5. 05*

   Machine Learning Optimized Search for the $Z^{\prime }$ from $U(1{)}_{L_{\mu }-L_{\tau }}$ at the LHC

   Manuel Drees🇩🇪 · Meng Shi🇩🇪 · Zhongyi Zhang🇳🇱

   Extending the Standard Model (SM) by a $U(1{)}_{L_{\mu }-L_{\tau }}$ group gives potentially significant new contributions to $g_{\mu }-2$, allows the construction of realistic neutrino mass matrices, incorporates lepton universality violation, and offers an anomaly-free mediator for a Dark Matter (DM) sector. In a recent analysis we showed that published LHC searches are not very sensitive to this model. Here we apply several Machine Learning (ML) algorithms in order to distinguish this model from the SM using simulated LHC data. In particular, we optimize the $3\mu$-signal, which has a considerably larger cross section than the $4\mu$-signal. Furthermore, since the $2$-muon plus missing $E_T$ final state gets contributions from diagrams involving DM particles, we optimize it as well. We find greatly improved sensitivity, which already for $36$ fb${}^{-1}$ of data exceeds the combination of published LHC and non-LHC results. We also emphasize the usefulness of Boosted Decision Trees which, unlike Neural Networks, easily allow to extract additional information from the data which directly connect to the theoretical model through feature importance. The same scheme could be used to analyze other models.

   hep-phhep-ex4 citations
6. 06*

   The strong first order electroweak phase transition in the $U(1{)}_X$SSM

   Shu-Min Zhao🇨🇳 · Jian-Fei Zhang🇨🇳 · Xi Wang🇨🇳 · Xing-Xing Dong🇨🇳 · Tai-Fu Feng🇨🇳

   In the $U(1{)}_X$ extension of the minimal supersymmetric standard model, there are three Higgs singlets and the corresponding trilinear terms in the Higgs effective potential. These new terms can allow a strongly first order electroweak phase transition(EWPT) for a wide parameter space. We use codes CosmoTransitions to analyze the thermal evolution of the Higgs effective potential and calculate nucleation temperature. To find reasonable parameter spaces for strongly first order EWPT, we randomly scan many parameters, which is numerically expensive. The diagrams are shown, that can lead to the 125 GeV Higgs mass and satisfy the first order EWPT. This work benefits the phenomenology of $U(1{)}_X$SSM and exploring new physics beyond the SM.

   hep-phPRD(2023)·1 citation
7. 07*

   The production of doubly charmed exotic hadrons in heavy ion collisions

   Yuanyuan Hu🇨🇳 · Jinfeng Liao🇺🇸 · Enke Wang🇨🇳 · Qian Wang🇨🇳 · Hongxi Xing🇨🇳 · Hui Zhang🇨🇳

   Hadron spectroscopy provides direct physical measurements that shed light on the non-perturbative behavior of quantum chromodynamics (QCD). In particular, various exotic hadrons such as the newly observed $T_{cc}^{+}$ by the LHCb collaboration, offer unique insights on the QCD dynamics in hadron structures. In this letter, we demonstrate how heavy ion collisions can serve as a powerful venue for hadron spectroscopy study of doubly charmed exotic hadrons by virtue of the extremely charm-rich environment created in such collisions. The yields of $T_{cc}^{+}$ as well as its potential isospin partners are computed within the molecular picture for Pb-Pb collisions at center-of-mass energy $2.76\mathrm{TeV}$. We find about three-order-of-magnitude enhancement in the production of $T_{cc}^{+}$ in Pb-Pb collisions as compared with the yield in proton-proton collisions, with a moderately smaller enhancement in the yields of the isospin partners $T_{cc}^0$ and $T_{cc}^{++}$. The $T_{cc}^{+}$ yield is comparable to that of the $X(3872)$ in the most central collisions while shows a considerably stronger decrease toward peripheral collisions, due to a "threshold" effect of the required double charm quarks for $T_{cc}^{+}$. Final results for their rapidity and transverse momentum $p_T$ dependence as well as the elliptic flow coefficient are reported and can be tested by future experimental measurements.

   hep-phhep-exnucl-exnucl-thPRD(2021)·56 citations
8. 08*

   LHAASO discovery of highest-energy photons towards new physics

   Chengyi Li🇨🇳 · Bo-Qiang Ma🇨🇳

   Ultrahigh-energy photons up to 1.4 peta-electronvolts have been observed by new cosmic-ray telescope in China -- a hint that Lorentz invariance might break down at the Planck-scale level.

   hep-phastro-ph.HEgr-qcSci.Bull.(2021)·10 citations
9. 09*

   Geometry and causality for efficient multiloop representations

   German F. R. Sborlini🇩🇪

   Multi-loop scattering amplitudes constitute a serious bottleneck in current high-energy physics computations. Obtaining new integrand level representations with smooth behaviour is crucial for solving this issue, and surpassing the precision frontier. In this talk, we describe a new technology to rewrite multi-loop Feynman integrands in such a way that non-physical singularities are avoided. The method is inspired by the Loop-Tree Duality (LTD) theorem, and uses geometrical concepts to derive the causal structure of any multi-loop multi-leg scattering amplitude. This representation makes the integrand much more stable, allowing faster numerical simulations, and opens the path for novel re-interpretations of higher-order corrections in QFT.

   hep-phhep-th5 citations
10. 10*

    A chiral model for sterile neutrino

    Chun Liu🇨🇳 · Yakefu Reyimuaji🇨🇳

    A model, which extends the standard model with a new chiral U(1)${}^{\prime }$ gauge symmetry sector, for the eV-mass sterile neutrino is constructed. It is basically fixed by anomaly free conditions. The lightness of the sterile neutrino has a natural explanation. As a by product, this model provides a WIMP-like dark matter candidate.

    hep-phJHEP(2021)·2 citations
11. 11*

    Weak transition form factors of heavy-light pseudoscalar mesons for space- and timelike momentum transfers

    Oliver Heger🇦🇹 · María Gómez-Rocha🇪🇸 · Wolfgang Schweiger🇦🇹

    Weak $B^{-}\to D^0,{\pi }^0$ and $D^{-}\to K^0,{\pi }^0$ transition form factors are described in both the space- and time-like momentum transfer regions, within a constituent-quark model. Neutrino-meson scattering and semileptonic weak decays are formulated within the point form of relativistic quantum mechanics to end up with relativistic invariant process amplitudes from which meson transition currents and form factors are extracted in an unambiguous way. For space-like momentum transfers, form factors depend on the frame in which the $WM{M}^{\prime }$ vertex is considered. Such a frame dependence is expected from a pure valence-quark picture, since a complete, frame independent description of form factors is supposed to include non-valence contributions. The most important of such contributions are the $Z$-graphs, which are, however, suppressed in the infinite-momentum frame ($q^2<0$). On the other hand, they can play a significant role in the Breit frame ($q^2<0$) and in the direct decay calculation ($q^2>0$), as a comparison with the infinite-momentum-frame form factors (analytically continued to $q^2>0$) reveals. Numerical results for the analytically continued infinite-momentum-frame form factors agree very well with lattice data in the time-like momentum transfer region and the experimental value for the slope of the $F_{B\to D}^{+}$ transition form factor at zero recoil is reproduced satisfactorily. These predictions satisfy heavy-quark-symmetry constraints and their $q^2$ dependence is well approximated by a pole fit, reminiscent of a vector-meson-dominance-like decay mechanism. We discuss how such a decay mechanism can be accommodated within an extension of our constituent-quark model, by allowing for a non-valence component in the meson wave functions. We also address the question of wrong cluster properties inherent in the Bakamjian-Thomas formulation.

    hep-phnucl-thPRD(2021)·7 citations
12. 12*

    Unbiased Elimination of Negative Weights in Monte Carlo Samples

    Jeppe R. Andersen🇬🇧 · Andreas Maier🇩🇪

    We propose a novel method for the elimination of negative Monte Carlo event weights. The method is process-agnostic, independent of any analysis, and preserves all physical observables. We demonstrate the overall performance and systematic improvement with increasing event sample size, based on predictions for the production of a W boson with two jets calculated at next-to-leading order perturbation theory.

    hep-phhep-exEPJC(2022)·31 citations
13. 13*

    Dark Matter Hot Spots and Neutrino Telescopes

    Stephan Meighen-Berger🇩🇪 · Martina Karl🇩🇪

    We perform a new dark matter hot spot analysis using ten years of public IceCube data. This analysis assumes dark matter self-annihilates to neutrino pairs and treats the production sites as discrete point sources. As a result, these sites will appear as hot spots in the sky for neutrino telescopes, possibly outshining other standard model neutrino sources. Compared to galactic center analyses, we show that this approach is a powerful tool capable of setting the highest neutrino detector limits for dark matter masses between 10 TeV and 100 PeV. This is due to the inclusion of spatial information in addition to the typically used energy deposition in the analysis.

    hep-phastro-ph.HE0 citations
14. 14*

    A three component model for hadron $p_{\mathrm{T}}$-spectra in pp and Pb-Pb collisions at the LHC

    Smbat Grigoryan🇷🇺

    A three component model, consisting of the hydrodynamical blast-wave term and two power-law terms, is proposed for an improved fitting of the hadron spectra measured at midrapidity and for arbitrary transverse momenta ($p_{\text{T}}$) in pp and heavy-ion collisions of different centralities at the LHC. The model describes well the available experimental data for all considered particles from pions to charmonia in pp at $\sqrt{s}=$ 2.76, 5.02, 7, 8 and 13 TeV and in Pb-Pb at $\sqrt{s_{\mathrm{NN}}}=$ 2.76 and 5.02 TeV.

    hep-phEPJA(2021)·5 citations
15. 15*

    Charmonium suppression in ultra-relativistic proton-proton collisions at LHC energies: A hint for QGP in small systems

    Captain R. Singh🇮🇳 · Suman Deb🇮🇳 · Raghunath Sahoo🇮🇳 · Jan-e Alam🇮🇳

    Proton-proton ($pp$) collision has been considered as a baseline to study the system produced in relativistic heavy-ion (AA) collisions with the basic assumption that no thermal medium is formed in $pp$ collisions. This warrants a cautious analysis of the system produced in $pp$ collisions at relativistic energies.In this work we investigate the charmonium suppression in $pp$ collisions at $\sqrt{s}=5.02,7$ and $13$ TeV energies. Further, charmonium suppression has been studied for various event multiplicities and transverse momenta by including the mechanisms of color screening, gluonic dissociation, collisional damping along with regeneration due to correlated $c\bar{c}$ pairs. Here we obtain a net suppression of charmonia at high-multiplicity events indicating the possibility of the formation of quark-gluon plasma in $pp$ collisions.

    hep-phhep-exnucl-exnucl-thEPJC(2022)·19 citations
16. 16*

    Emergent new symmetry from the Higgs shadow

    Waleed Abdallah🇪🇬 · Anjan Kumar Barik🇮🇳 · Santosh Kumar Rai🇮🇳 · Tousik Samui🇮🇳

    We show in this Letter how a new hidden gauge symmetry responsible for neutrino mass as well as dark matter (DM) in the Universe can be discovered through scalar mediators responsible for breaking the new symmetry. The new force mediator ($Z^{\prime }$) may be lighter than the Standard Model (SM) gauge bosons but cannot be observed in traditional searches for new gauge bosons. We highlight a novel way of discovering such a symmetry at the Large Hadron Collider (LHC) by incorporating an existing ATLAS analysis on four lepton final states which include the Higgs resonance. In addition, we show that the hidden sector also introduces flavor violation in the lepton sector which can become a significant channel of discovery for the new force.

    hep-phhep-exPRD(2023)·8 citations
17. 17*

    Heavy-meson chiral Lagrangians, effective flavored couplings, SU(4) flavor breaking and their consequences

    Bruno El-Bennich🇧🇷 · Fernando E. Serna🇧🇷

    We review heavy quark flavor and spin symmetries, their exploitation in heavy meson effective theories and the flavored couplings of charmed and light mesons in the definition of their effective Lagrangians. We point out how nonperturbative continuum QCD approaches based on Dyson-Schwinger and Bethe-Salpeter equations can be used to calculate strong and leptonic decays of open-charm mesons and heavy quarkonia. The strong decay $D^{\ast }\to D\pi$ serves as a benchmark, as it is the only physical open-charm observable that can be related to the effective Lagrangian's couplings. Nonetheless, a quantitative comparison of $D^{\ast }D\pi$, $\rho DD$, $\rho D^{\ast }D$ and $\rho D^{\ast }{D}^{\ast }$ couplings for a range of off-shell momenta of the $\rho$-meson invalidates SU(4)${}_F$ symmetry relations between these couplings. Thus, besides the breaking of flavor symmetry by mass terms in the Lagrangians, the flavor-symmetry breaching in couplings and their dependence on the $\rho$-meson virtuality cannot be ignored. We also take the opportunity to present new results for the effective $J/\psi DD$ and $J/\psi D^{\ast }D$ couplings. We conclude this contribution with a discussion on how the description of pseudoscalar and vector $D$, $D_s$, $B$ and $B_s$ meson properties can be drastically improved with a modest modification of the flavor-dependence in the Bethe-Salpeter equation.

    hep-phhep-exhep-latnucl-thPoS(2021)·4 citations
18. 18*

    Exotic fully-heavy $Q\bar{Q}Q\bar{Q}$ tetraquark states in $8_{[Q\bar{Q}]}\otimes 8_{[Q\bar{Q}]}$ color configuration

    Qi-Nan Wang🇨🇳 · Zi-Yan Yang🇨🇳 · Wei Chen🇨🇳

    We have systematically calculated the mass spectra for S-wave and P-wave fully-charm $c\bar{c}c\bar{c}$ and fully-bottom $b\bar{b}b\bar{b}$ tetraquark states in the $8_{[Q\bar{Q}]}\otimes 8_{[Q\bar{Q}]}$ color configuration, by using the moment QCD sum rule method. The masses for the fully-charm $c\bar{c}c\bar{c}$ tetraquark states are predicted about $6.3-6.5$ GeV for S-wave channels and $7.0-7.2$ GeV for P-wave channels. These results suggest the possibility that there are some $8_{[c\bar{c}]}\otimes 8_{[c\bar{c}]}$ components in LHCb's di-$J/\psi$ structures. For the fully-bottom $b\bar{b}b\bar{b}$ system, their masses are calculated around 18.2 GeV for S-wave tetraquark states while 18.4-18.8 GeV for P-wave ones, which are below the ${\eta }_b{\eta }_b$ and ${\rm Y}(1S){\rm Y}(1S)$ two-meson decay thresholds.

    hep-phhep-exPRD(2021)·38 citations
19. 19*

    COHERENT constraints on $Z^{\prime }$ in 331$\beta$ model

    D. T. Binh🇻🇳 · L. T. Hue🇻🇳 · V. H. Binh🇻🇳 · D. V. Soa🇻🇳 · H. N. Long🇻🇳

    We investigate coherent-elastic neutrino-nucleus scattering ($CE\nu NS$) in 3-3-1 models for different values of $\beta$ in which $\beta$ is a parameter used to define the charge operator of the 331 models. We show that the number of events predicted by 331$\beta$ model is in agreement with the data given by COHERENT experiment. We evaluate the sensitivity of the mass of Z' boson with 90% confidence level (CL) and find that $m_{Z^{\prime }}\ge 1.4$TeV for $\beta =-\sqrt{3}$ with 90% CL. We perform ${\chi }^2$ fit for liquid Argon, Germanium and NaI detector subsystems, we obtain $m_{Z^{\prime }}\ge [2,3.1]$ TeV with 90\% CL. Our results indicate low-energy high-intensity measurements can provide a valuable probe, complementary to high energy collider searches at LHC and electroweak precision measurements.

    hep-ph3 citations
20. 20*

    An Altarelli Cocktail for the MiniBooNE Anomaly?

    Vedran Brdar (Fermilab and Northwestern U)🇺🇸 · Joachim Kopp (CERN and JGU Mainz)🇨🇭

    We critically examine a number of theoretical uncertainties affecting the MiniBooNE short-baseline neutrino oscillation experiment in an attempt to better understand the observed excess of electron-like events. We re-examine the impact of fake charged current quasi-elastic (CCQE) events, the background due to neutral current ${\pi }^0$ production, and the single-photon background. For all processes, we compare the predictions of different event generators (GENIE, GiBUU, NUANCE, and NuWro) and, for GENIE, of different tunes. Where MiniBooNE uses data-driven background predictions, we discuss the uncertainties affecting the relation between the signal sample and the control sample. In the case of the single-photon background, we emphasize the uncertainties in the radiative branching ratios of heavy hadronic resonances. We find that not even a combination of uncertainties in different channels adding up unfavorably (an "Altarelli cocktail") appears to be sufficient to resolve the MiniBooNE anomaly. We finally investigate how modified background predictions affect the fit of a $3+1$ sterile neutrino scenario. We carefully account for full four-flavor oscillations not only in the signal, but also in the background and control samples. We emphasize that because of the strong correlation between MiniBooNE's ${\nu }_e$ and ${\nu }_{\mu }$ samples, a sterile neutrino mixing only with ${\nu }_{\mu }$ is sufficient to explain the anomaly, even though the well-known tension with external constraints on ${\nu }_{\mu }$ disappearance persists.

    hep-phhep-exPRD(2022)·38 citations
21. 21*

    A Cautionary Tale of Decorrelating Theory Uncertainties

    Aishik Ghosh🇺🇸 · Benjamin Nachman🇺🇸

    A variety of techniques have been proposed to train machine learning classifiers that are independent of a given feature. While this can be an essential technique for enabling background estimation, it may also be useful for reducing uncertainties. We carefully examine theory uncertainties, which typically do not have a statistical origin. We will provide explicit examples of two-point (fragmentation modeling) and continuous (higher-order corrections) uncertainties where decorrelating significantly reduces the apparent uncertainty while the actual uncertainty is much larger. These results suggest that caution should be taken when using decorrelation for these types of uncertainties as long as we do not have a complete decomposition into statistically meaningful components.

    hep-phcs.LGhep-exEPJC(2022)·37 citations
22. 22*

    LC Circuits for the Direct Detection of Ultralight Dark Matter Candidates

    Christopher M. Donohue🇺🇸 · Susan Gardner🇺🇸 · Wolfgang Korsch🇺🇸

    Cosmological mechanisms that yield ultralight dark matter are insensitive to the intrinsic parity of a bosonic dark matter candidate, but that same quantity plays a crucial role in a direct detection experiment. The modification of electrodynamics in the presence of ultralight axion-like dark matter is well-known and has been used to realize sensitive probes of such sub-eV mass-scale dark matter, and analogous studies exist for hidden-photon dark matter as well. Here we reframe the modification of electrodynamics for ultralight dark matter of positive intrinsic parity, with a focus on the scalar case. In particular, we show that resonant LC circuit searches for axions can be modified to detect scalar dark matter particles by exploiting the large electric fields developed for use in neutron EDM experiments. Our proposed experimental set-up can improve upon previous sensitive searches for scalar particles from "light shining through a wall" experiments to probe scalar-photon couplings some three orders of magnitude smaller in the $1\times 10^{-11}-4\times 10^{-8}$ eV mass ($2\mathrm{kHz}-10\mathrm{MHz}$ frequency) range.

    hep-phastro-ph.CO6 citations
23. 23*

    CFTs Blueshift Tensor Fluctuations Universally

    Matthew Baumgart🇺🇸 · Jonathan J. Heckman🇺🇸 · Logan Thomas🇺🇸

    The strong constraints of conformal symmetry cause any nearly-conformal sector to blueshift tensor fluctuations in cosmology. Hidden sectors with approximate conformal symmetry, which may be quite large, are a well-motivated extension of physics beyond the Standard Models of particle physics and cosmology. They can therefore lead to a detectable shift in the tensor tilt for next-generation CMB and gravitational wave experiments. We compute the leading-order contribution to the in-in graviton two-point function from virtual loops in such sectors to demonstrate this universal effect. In units where a single conformally-coupled scalar is 1, limits from Stage-IV CMB experiments could bound the size of this extra sector to be smaller than about 10^15. This would be sufficient to rule out N-Naturalness as a complete resolution of the hierarchy problem.

    hep-phastro-ph.COgr-qchep-thJCAP(2022)·26 citations
24. 24*

    Mean-field update in the JAM microscopic model: Mean-field effects on collective flow in high-energy heavy-ion collisions at $\sqrt{s_{NN}}=2-20$ GeV energies

    Yasushi Nara🇯🇵 · Akira Ohnishi🇯🇵

    The beam energy dependence of the directed flow is a sensitive probe for the properties of strongly interacting matter. We consider different implementations of momentum-dependent hadronic mean fields in the relativistic quantum molecular dynamics (RQMD) framework. First, Lorentz scalar implementation of a Skyrme type potential is examined. Then, full implementation of the Skyrme type potential as a Lorentz vector in the RQMD approach is proposed. We find that scalar implementation of the Skyrme force is too weak to generate repulsion explaining observed data of sideward flows at $\sqrt{s_{NN}}<10$ GeV, while vector implementation gives collective flows compatible with the data for a wide range of beam energies $2.7<\sqrt{s_{NN}}<20$ GeV. We show that our approach reproduces the negative proton directed flow at $\sqrt{s_{NN}}>10$ GeV discovered by experiments. We discuss the dynamical generation mechanisms of the directed flow within a conventional hadronic mean field. A positive slope of proton directed flow is generated predominantly during compression stages of heavy-ion collisions by the strong repulsive interaction due to high baryon densities. In contrast, in the expansion stages of the collision, the negative directed flow is generated more strongly than the positive one by the tilted expansion and shadowing by the spectator matter. At lower collision energies $\sqrt{s_{NN}}<10$ GeV, the positive flow wins against the negative flow because of a long compression time. On the other hand, at higher energies $\sqrt{s_{NN}}>10$ GeV, negative flow wins because of shorter compression time and longer expansion time. A transition beam energy from positive to negative flow is highly sensitive to the strength of the interaction.

    ↳ nucl-thhep-phnucl-exPRC(2022)·64 citations
25. 25*

    Constraints on quantum gravity and the photon mass from gamma ray bursts

    Deaglan J. Bartlett🇬🇧 · Harry Desmond🇬🇧 · Pedro G. Ferreira🇬🇧 · Jens Jasche🇸🇪

    Lorentz invariance violation in quantum gravity (QG) models or a nonzero photon mass, $m_{\gamma }$, would lead to an energy-dependent propagation speed for photons, such that photons of different energies from a distant source would arrive at different times, even if they were emitted simultaneously. By developing source-by-source, Monte Carlo-based forward models for such time delays from gamma ray bursts, and marginalising over empirical noise models describing other contributions to the time delay, we derive constraints on $m_{\gamma }$ and the QG length scale, ${\ell }_{\mathrm{QG}}$, using spectral lag data from the BATSE satellite. We find $m_{\gamma }<4.0\times 10^{-5}h\mathrm{eV}/c^2$ and ${\ell }_{\mathrm{QG}}<5.3\times 10^{-18}h\mathrm{Ge}{\mathrm{V}}^{-1}$ at 95% confidence, and demonstrate that these constraints are robust to the choice of noise model. The QG constraint is among the tightest from studies which consider multiple gamma ray bursts and the constraint on $m_{\gamma }$, although weaker than from using radio data, provides an independent constraint which is less sensitive to the effects of dispersion by electrons.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-phPRD(2021)·21 citations
26. 26*

    New electroweak challenges and opportunities at the LHeC

    Krzysztof Piotrzkowski🇧🇪 · Yuji Yamazaki🇯🇵

    The Large Hadron-Electron Collider (LHeC) will operate at $\sqrt{s}$ = 1.2 TeV and accumulate about 1/ab of integrated electron-proton luminosity. Novel studies of high energy photon-photon interactions at the LHeC, at the $\gamma \gamma$ center-of-mass energy up to 1 TeV, will open new frontiers in the electroweak physics as well as in searches for physics beyond the Standard Model. Despite a very high $ep$ luminosity, the experimental conditions will be very favorable at the LHeC - a negligible event pileup will allow for unique studies of a number of processes involving the exclusive production via photon-photon fusion.

    ↳ hep-exhep-phPoS(2022)·0 citations
27. 27*

    Impact of Dark Compton Scattering on Direct Dark Matter Absorption Searches

    Yonit Hochberg🇮🇱 · Belina von Krosigk🇩🇪 · Eric Kuflik🇮🇱 · To Chin Yu🇺🇸

    Direct detection experiments are gaining in mass reach. Here we show that the inclusion of dark Compton scattering, which has typically been neglected in absorption searches, has a substantial impact on the reach and discovery potential of direct detection experiments at high bosonic cold dark matter masses. We demonstrate this for relic dark photons and axion-like particles: we improve expected reach across materials, and further use results from SuperCDMS, EDELWEISS and GERDA to place enhanced limits on dark matter parameter space. We outline the implications for detector design and analysis.

    ↳ hep-exhep-phPRL(2022)·14 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.