Fri·Jul 26, 2019Friday·July 26, 2019

1. 01*

   Sub-MeV Dark Matter and the Goldstone Modes of Superfluid Helium

   Andrea Caputo🇪🇸 · Angelo Esposito🇨🇭 · Antonio D. Polosa🇮🇹

   We show how the relativistic effective field theory for the superfluid phase of helium-4 can replace the standard methods used to compute the production rates of low momentum excitations due to the interaction with an external probe. This is done by studying the scattering problem of a light dark matter particle in the superfluid, and comparing to some existing results. We show that the rate of emission of two phonons, the Goldstone modes of the effective theory, gets strongly suppressed for sub-MeV dark matter particles due to a fine cancellation between two different tree-level diagrams in the limit of small exchanged momenta. This phenomenon is found to be a consequence of the particular choice of the potential felt by the dark matter particle in helium. The predicted rates can vary by orders of magnitude if this potential is changed. We prove that the dominant contribution to the total emission rate is provided by the phonons. Finally, we analyze the angular distributions for the emissions of one and two phonons, and discuss how they can be used to measure the mass of the hypothetical dark matter particle hitting the helium target.

   hep-phastro-ph.COhep-exPRD(2019)·61 citations
2. 02*

   Stitching an Asymmetric Texture with ${\mathcal{T}}_{13}\times {\mathcal{Z}}_5$ Family Symmetry

   M. Jay Pérez🇺🇸 · Moinul Hossain Rahat🇺🇸 · Pierre Ramond🇺🇸 · Alexander J. Stuart🇲🇽 · Bin Xu🇺🇸

   We propose ${\mathcal{T}}_{13}={\mathcal{Z}}_{13}⋊{\mathcal{Z}}_3$ as the underlying non-Abelian discrete family symmetry of the asymmetric texture presented in arXiv:1805.10684 [hep-ph]. Its mod 13 arithmetic distinguishes each Yukawa matrix element of the texture. We construct a model of effective interactions that singles out the asymmetry and equates, without fine-tuning, the products of down-quark and charged-lepton masses at a GUT-like scale.

   hep-phPRD(2019)·27 citations
3. 03*

   A comparative study between the modified Fritzsch and nearest neighbor interaction textures

   J. D. García-Aguilar🇲🇽 · Juan Carlos Gómez-Izquierdo🇲🇽

   From mass textures point of view, we present a comparative study of the ${\mathbf{S}}_3$ flavor symmetry in the left-right symmetry model (LRSM) and the baryon minus lepton model (BLM) taking into account their predictions on the CKM mixing matrix. To do this, we recover the already studied quark mass matrix, that comes from some published papers, and under certain strong assumption, one can show that there are predictive scenarios in the LRSM and BLM where the modified Fritzsch and nearest neighbor interaction (NNI) textures drive respectively the quark mixings. As main result, the CKM mixing matrix is in good agreement with the last experimental data in the flavored BLM model.

   hep-phInt.J.Mod.Phys.A(2019)·1 citation
4. 04*

   Analysis of the axialvector $B_c$-like tetraquark states with the QCD sum rules

   Zhi-Gang Wang🇨🇳

   In this article, we construct the diquark-antidiquark type current operators to study the axialvector $B_c$-like tetraquark states with the QCD sum rules. In calculations, we take the energy scale formula as a powerful constraint to choose the ideal energy scales of the QCD spectral densities and add detailed discussions to illustrate why we take the energy scale formula to improve the QCD sum rules for the doubly heavy tetraquark states. The predicted masses $M_{Z_{\bar{b}c}(1^{+-})}=7.30\pm 0.08\mathrm{GeV}$ and $M_{Z_{\bar{b}c}(1^{++})}=7.31\pm 0.08\mathrm{GeV}$ lie between the conventional $2\mathrm{P}$ and $3\mathrm{P}$ $B_c$ states with $J^P=1^{+}$ from the potential quark models, which is a typical feature of the diquark-antidiquark type $B_c$-like tetraquark states.

   hep-phEPL(2019)·11 citations
5. 05*

   Temperature and fluid velocity on the freeze-out surface from $\pi$, $K$, $p$ spectra in pp, p--Pb and Pb--Pb collisions

   Aleksas Mazeliauskas🇨🇭 · Vytautas Vislavicius🇩🇰

   We present a new approach to take into account resonance decays in the blast-wave model fits of identified hadron spectra. Thanks to pre-calculated decayed particle spectra, we are able to extract, in a matter of seconds, the multiplicity dependence of the single freeze-out temperature $T_{\mathrm{fo}}$, average fluid velocity $⟨{\beta }_{\mathrm{T}}⟩$, velocity exponent $n$, and the volume $dV/dy$ of an expanding fireball. In contrast to blast-wave fits without resonance feed-down, our approach results in a freeze-out temperature of $T_{\mathrm{fo}}\approx 150\text{MeV}$, which has only weak dependence on multiplicity and collision system. Finally, we discuss separate chemical and kinetic freeze-outs separated by partial chemical equilibrium.

   hep-phnucl-exnucl-thPRC(2020)·49 citations
6. 06*

   Precision calculations of $B\to V$ form factors in QCD

   Jing Gao🇨🇳 · Cai-Dian Lü🇨🇳 · Yue-Long Shen🇨🇳 · Yu-Ming Wang🇨🇳 · Yan-Bing Wei🇨🇳

   Applying the vacuum-to-$B$-meson correlation functions with an interpolating current for the light vector meson we construct the light-cone sum rules (LCSR) for the "effective" form factors ${\xi }_{\parallel }(n\cdot p)$, ${\xi }_{\perp }(n\cdot p)$, ${\Xi }_{\parallel }(\tau ,n\cdot p)$ and ${\Xi }_{\perp }(\tau ,n\cdot p)$, defined by the corresponding hadronic matrix elements in soft-collinear effective theory (SCET), entering the leading-power factorization formulae for QCD form factors responsible for $B\to V\ell {\bar{\nu }}_{\ell }$ and $B\to V\ell \bar{\ell }$ decays at large hadronic recoil at next-to-leading-order in QCD. The light-quark mass effect for the local SCET form factors ${\xi }_{\parallel }(n\cdot p)$ and ${\xi }_{\perp }(n\cdot p)$ is also computed from the LCSR method with the $B$-meson light-cone distribution amplitude ${\varphi }_B^{+}(\omega ,\mu )$ at $\mathcal{O}({\alpha }_s)$. Furthermore, the subleading power corrections to $B\to V$ form factors from the higher-twist $B$-meson light-cone distribution amplitudes are also computed with the same method at tree level up to the twist-six accuracy. Having at our disposal the LCSR predictions for $B\to V$ form factors, we further perform new determinations of the CKM matrix element $|V_{ub}|$ from the semileptonic $B\to \rho \ell {\bar{\nu }}_{\ell }$ and $B\to \omega \ell {\bar{\nu }}_{\ell }$ decays, and predict the normalized differential branching fractions and the $q^2$-binned $K^{\ast }$ longitudinal polarization fractions of the exclusive rare $B\to K^{\ast }{\nu }_{\ell }{\bar{\nu }}_{\ell }$ decays.

   hep-phhep-exhep-latPRD(2020)·114 citations
7. 07*

   Collinear Drop

   Yang-Ting Chien🇺🇸 · Iain W. Stewart🇺🇸

   We introduce collinear drop jet substructure observables, which are unaffected by contributions from collinear radiation, and systematically probe soft radiation within jets. These observables can be designed to be either sensitive or insensitive to process-dependent soft radiation originating from outside the jet. Such collinear drop observables can be exploited as variables to distinguish quark, gluon, and color neutral initiated jets, for testing predictions for perturbative soft radiation in Monte Carlo simulations, for assessing models and universality for hadronization corrections, for examining the efficiency of pileup subtraction methods, and for any other application that leaves an imprint on soft radiation. We discuss examples of collinear drop observables that are based both on clustering and on jet shapes. Using the soft-collinear effective theory we derive factorization expressions for collinear drop observables from QCD jets, and carry out a resummation of logarithmically enhanced contributions at next-to-leading-logarithmic order. We also identify an infinite class of collinear drop observables for which the leading double logarithms are absent.

   hep-phhep-exnucl-thJHEP(2020)·29 citations
8. 08*

   Meson exchange between initial and final state and the $R_D$ ratio in the $\bar{B}\to D\bar{\nu }\ell ({\bar{\nu }}_{\tau }\tau )$ reactions

   Natsumi Ikeno🇯🇵 · Lianrong Dai🇨🇳 · Eulogio Oset🇪🇸

   We perform a calculation of the strong interaction effects between the $B$ and $D$ mesons in the $\bar{B}\to D\bar{\nu }\ell$ reaction, as a crossing process of reactions with $BD$ in the final state, where the strong interaction between the mesons leads to a bound $BD$ state. We find corrections to the tree level amplitude of the order of $15-25\%$. We further see the effect of the corrections studied in the $R_D$ ratio for the rates of $\bar{B}\to D{\bar{\nu }}_{\tau }\tau$ and $\bar{B}\to D{\bar{\nu }}_e\ell$ decays and find corrections of the order of $10\%$. Given the claims of $1.5\%$ precision in this ratio from fits to data within the standard model, any theoretical model aiming at describing this ratio within the same precision must take into account the corrections described in the present work.

   hep-phEPJA(2020)·3 citations
9. 09*

   Shear viscosity and electrical conductivity of relativistic fluid in presence of magnetic field: a massless case

   Jayanta Dey🇮🇳 · Sarthak Satapathy🇮🇳 · Prasanta Murmu🇮🇳 · Sabyasachi Ghosh🇮🇳

   We have explored the shear viscosity and electrical conductivity calculations for bosonic and fermionic medium, which goes from without to with magnetic field picture and then their simplified massless expressions. In presence of magnetic field, 5 independent velocity gradient tensors can be designed, so their corresponding proportional coefficients, connected with the viscous stress tensor provide us 5 shear viscosity coefficients. In existing litterateurs, two sets of tensors are available. Starting from them, present work has obtained two sets of expressions for 5 shear viscosity coefficients, which can be ultimately classified into three basic components: parallel, perpendicular and Hall components as one get same for electrical conductivity at finite magnetic field. Our calculations are based on kinetic theory approach in relaxation time approximation. Repeating same mathematical steps for finite magnetic field picture, which traditionally practiced for without field case, we have obtained 2 sets of 5 shear viscosity components, whose final expressions are in well agreements with earlier references, although a difference in methodology or steps can be clearly noticed. Realizing the massless results of viscosity and conductivity for Maxwell-Boltzmann, Fermi-Dirac and Bose-Einstein distribution function, we have applied them for massless quark gluon plasma and hadronic matter phases, which can provide us a rough order of strength, within which actual results will vary during quark-hadron phase transition. Present work also indicates that magnetic field might have some role for building perfect fluid nature in RHIC or LHC matter. The lower bound expectation of shear viscosity to entropy density ratio is also discussed.

   hep-phnucl-thPramana(2021)·47 citations
10. 10*

    Applications of the WW-type approximation to SIDIS

    S. Bastami🇺🇸 · H. Avakian🇺🇸 · A. V. Efremov🇷🇺 · A. Kotzinian🇦🇲 · B. U. Musch🇩🇪 · B. Parsamyan🇨🇭 · A. Prokudin🇺🇸 · M. Schlegel🇺🇸 · G. Schnell🇪🇸 · P. Schweitzer🇺🇸 · K. Tezgin🇺🇸

    We explore the complete cross-section for the production of unpolarized hadrons in semi-inclusive deep-inelastic scattering up to power-suppressed $\mathcal{O}(1/Q^2)$ terms in the Wandzura-Wilczek-type (WW-type) approximation, which consists in systematically assuming that $\bar{q}gq$-correlators are much smaller than $\bar{q}q$-correlators. Under the applicability of WW-type approximations, certain relations among transverse momentum dependent parton distribution functions (TMDs) and fragmentation functions (FFs) occur which are used to approximate SIDIS cross-section in terms of a smaller subset of TMDs and FFs. We discuss the applicability of the WW-type approximations on the basis of available data.

    hep-phPoS(2019)·1 citation
11. 11*

    Energy-momentum tensor densities in the bag model

    M. J. Neubelt🇺🇸 · A. Sampino🇺🇸 · J. Hudson🇺🇸 · K. Tezgin🇺🇸 · P. Schweitzer🇺🇸

    The form factors of the energy-momentum tensor can be accessed via studies of generalized parton distributions in hard exclusive reactions. In this talk we present recent results on the energy-momentum tensor form factors and densities in the bag model formulated in the large-$N_c$ limit. The simplicity and lucidity of this quark model allow us to investigate many general concepts which have recently attracted interest, including pressure, shear forces and angular momentum density inside the nucleon. The results from the bag model are theoretically consistent, and comply with all general requirements.

    hep-phPoS(2019)·2 citations
12. 12*

    Searches for Connections Between Dark Matter and Neutrinos with the IceCube High-Energy Starting Event Sample

    Carlos A. Argüelles🇺🇸 · Hrvoje Dujmovic (for the IceCube Collaboration)🇰🇷

    The nature of dark matter remains one of the most important open questions in physics. Although dark matter effects have only been observed gravitationally, the order-one ratio between conventional matter and dark matter hints to a non-gravitational link between them. In this contribution, we search for such a link using the IceCube high-energy starting event (HESE) sample, which contains some of the highest energy neutrinos ever observed. These are dominated by a yet unidentified high-energy diffuse astrophysical component. Using these events we look for evidence of an excess due to dark matter decay or annihilation, and also for a novel signature due to high-energy neutrinos scattering with dark matter. Finally, in this contribution, we will summarize and highlight the complementarity between the obtained limits for these two scenarios.

    hep-phhep-exPoS(2020)·21 citations
13. 13*

    Hunting scalar leptoquarks with boosted tops and light leptons

    Kushagra Chandak🇮🇳 · Tanumoy Mandal🇸🇪 · Subhadip Mitra🇮🇳

    The LHC search strategies for leptoquarks that couple dominantly to a top quark are different than for the ones that couple mostly to the light quarks. We consider charge $1/3$ (${\varphi }_1$) and $5/3$ (${\varphi }_5$) scalar leptoquarks that can decay to a top quark and a charged lepton ($t\ell$) giving rise to a resonance system of a boosted top and a high-$p_{\mathrm{T}}$ lepton. We introduce simple phenomenological models suitable for bottom-up studies and explicitly map them to all possible scalar leptoquark models within the Buchmüller-Rückl-Wyler classifications that can have the desired decays. We study pair and single productions of these leptoquarks. Contrary to the common perception, we find that the single production of top-philic leptoquarks $\varphi =\{{\varphi }_1,{\varphi }_5\}$ in association with a lepton and jets could be significant for order one $\varphi t\ell$ coupling in certain scenarios. We propose a strategy of selecting events with at least one hadronic-top and two high-$p_{\mathrm{T}}$ same flavour opposite sign leptons. This captures events from both pair and single productions. Our strategy can significantly enhance the LHC discovery potential especially in the high-mass region where single productions become more prominent. Our estimation shows that a scalar leptoquark as heavy as $\sim 1.7$ TeV can be discovered at the $14$ TeV LHC with 3 ab${}^{-1}$ of integrated luminosity in the $t\ell \ell +X$ channel for $100\%$ branching ratio in the $\varphi \to t\ell$ decay mode. However, in some scenarios, the discovery reach can increase beyond $2$ TeV even though the branching ratio comes down to about $50\%$.

    hep-phhep-exPRD(2019)·48 citations
14. 14*

    UV completion of an axial, leptophobic, $Z^{\prime }$

    J. A. Casas🇪🇸 · M. Chakraborti🇪🇸 · J. Quilis🇪🇸

    The $Z^{\prime }$-portal is one of most popular and well-explored scenarios of dark matter (DM). To avoid the strong constraints coming from dilepton resonance searches at the LHC and direct detection of DM, it is usually required that in addition to being leptophobic, the $Z^{\prime }$ is axially coupled to either the (fermionic) DM or the standard model (SM) quarks. The first possibility has been extensively studied both in the context of simplified model and UV complete scenarios. However, the studies on the second possibiliy are largely confined to simplified models only. Here, we construct the minimal UV completion of these models satisfying both the criteria of leptophobia and purely axial $Z^{\prime }-$quark coupling. The anomaly cancellation conditions demand highly non-trivial structures, not only in the dark sector, but also in the Higgs sector.

    hep-phPLB(2020)·4 citations
15. 15*

    Model independent determination of the spins of the $P_c$(4440) and $P_c$(4457) from the spectroscopy of the triply charmed dibaryons

    Ya-Wen Pan🇨🇳 · Ming-Zhu Liu🇨🇳 · Fang-Zheng Peng🇨🇳 · Mario Sánchez Sánchez🇫🇷 · Li-Sheng Geng🇨🇳 · Manuel Pavon Valderrama🇨🇳

    The LHCb collaboration has recently observed three narrow pentaquark states --- the $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ ---that are located close to the $\bar{D}{\Sigma }_c$ and ${\bar{D}}^{\ast }{\Sigma }_c$ thresholds. Among the so-far proposed theoretical interpretations for these pentaquarks, the molecular hypothesis seems to be the preferred one. Nevertheless, in the molecular picture the spins of the $P_c(4440)$ and $P_c(4457)$ have not been unambiguously determined yet. In this letter we point out that heavy antiquark-diquark symmetry induces a model-independent relation between the spin-splitting in the masses of the $P_c(4440)$ and $P_c(4457)$ ${\bar{D}}^{\ast }{\Sigma }_c$ pentaquarks and the corresponding splitting for the $0^{+}$ and $1^{+}$ ${\Xi }_{cc}{\Sigma }_c$ triply charmed dibaryons. This is particularly relevant owing to a recent lattice QCD prediction of the $1^{+}$ triply charmed dibaryon, which suggests that a calculation of the mass of its $0^{+}$ partner might be within reach. This in turn would reveal the spins of the $P_c(4440)$ and $P_c(4457)$ pentaquarks, providing a highly nontrivial test of heavy-quark symmetry and the molecular nature of the pentaquarks. Furthermore, the molecular interpretation of the hidden-charm pentaquarks implies the existence of a total of ten triply charmed dibaryons as ${\Xi }_{cc}^{(\ast )}{\Sigma }_c^{(\ast )}$ molecules, which, if confirmed in the lattice, will largely expand our understanding of the non-perturbative strong interaction in the heavy-quark sector.

    hep-phhep-exhep-latPRD(2020)·44 citations
16. 16*

    Decaying dark matter at IceCube and its signature on High Energy gamma experiments

    Marco Chianese🇳🇱 · Damiano F. G. Fiorillo🇮🇹 · Gennaro Miele🇮🇹 · Stefano Morisi🇮🇹 · Ofelia Pisanti🇮🇹

    The origin of neutrino flux observed in IceCube is still mainly unknown. Typically two flux components are assumed, namely: atmospheric neutrinos and an unknown astrophysical term. In principle the latter could also contain a top-down contribution coming for example from decaying dark matter. In this case one should also expect prompt and secondary gammas as well. This leads to the possibility of a multimessenger analysis based on the simultaneous comparison of the Dark Matter hypothesis both with neutrino and high energy gamma rays data. In this paper, we analyze, for different decaying Dark Matter channels, the 7.5 years IceCube HESE data, and compare the results with previous exclusion limits coming from Fermi data. Finally, we test whether the Dark Matter hypothesis could be further scrutinised by using forthcoming high energy gamma rays experiments.

    hep-phastro-ph.COastro-ph.HEhep-exJCAP(2019)·51 citations
17. 17*

    Dark Matter from self-dual gauge/Higgs dynamics

    Dario Buttazzo🇮🇹 · Luca Di Luzio🇮🇹 · Giacomo Landini🇮🇹 · Alessandro Strumia🇮🇹 · Daniele Teresi🇮🇹

    We show that a new gauge group with one new scalar leads to automatically stable Dark Matter candidates. We consider theories where the Higgs phase is dual to the confined phase: it is known that SU(2) gauge theories with a scalar doublet (like the Standard Model) obey this non-trivial feature. We provide a general criterion, showing that this self-duality holds for SU(N), SO(N), Sp(N) and G_2 gauge dynamics with a scalar field in the fundamental representation. The resulting Dark Matter phenomenology has non-trivial features that are characteristic of the group, and that we discuss case by case. Just to mention a few, SU(N) has an accidental conserved dark baryon number, SO(2N+1) leads to stable glue-balls thanks to a special parity, G_2 leads to a Dark Matter system analogous to neutral kaons. The cosmological Dark Matter abundance is often reproduced for masses around 100 TeV: all constraints are satisfied and lighter dark glue-balls can affect Higgs physics. These theories acquire additional interest and predictivity assuming that both the dark and weak scales are dynamically generated.

    hep-phastro-ph.COhep-thJHEP(2019)·20 citations
18. 18*

    Application of the Thomas Fermi Quark Model to Multiquark Mesons

    Suman Baral🇺🇸 · Walter Wilcox🇺🇸

    The possibility of the existence of mesons with two or more quark-antiquark pairs is investigated with a new application of the Thomas-Fermi (TF) statistical quark model. Quark color couplings are treated in a mean field manner similar to a previous application to baryons, and short and concise expressions for energies are derived. We find that, on average, quarks only interact with antiquarks in such systems. The TF differential equation is constructed and systems with heavy-light quark content are examined. Three types of mesonic systems are defined. In the case of charm quarks, multi-charmonium, multi-$Z$ meson and multi-$D$ meson family types are examined. System analogs for bottom quarks are also constructed. Quantitative trends for system energies of mesonic quark matter are extracted as a function of the number of quark pairs. We find indications from energy plots that multi-$Z$ type mesons (and their bottom quark analogs) are actually stable for a range of quark number pairs. At this initial stage we have not yet included explicit spin interaction couplings between quarks, but we can take one level of degeneracy into account in our two-inequivalent TF function construction.

    hep-phhep-latNPA(2019)·3 citations
19. 19*

    Modification of Jet Substructure in Heavy Ion Collisions as a Probe of the Resolution Length of Quark-Gluon Plasma

    J. Casalderrey-Solana🇪🇸 · G. Milhano🇵🇹 · D. Pablos🇳🇴 · K. Rajagopal🇺🇸

    We present an analysis of the role that the quark-gluon plasma (QGP) resolution length, the minimal distance by which two nearby colored charges in a jet must be separated such that they engage with the plasma independently, plays in understanding the modification of jet substructure due to interaction with QGP. We identify a set of observables that are sensitive to whether jets are quenched as if they are single energetic colored objects or whether the medium that quenches them has the ability to resolve the internal structure of the jet. Using the hybrid strong/weak coupling model, we find that although the ungroomed jet mass is not suitable for this purpose (because it is more sensitive to effects coming from particles reconstructed as a part of a jet that originate from the wake that the jet leaves in the plasma), groomed observables such as the number of Soft Drop splittings $n_{\mathrm{SD}}$, the momentum sharing fraction $z_g$, or the groomed jet mass are particularly well-suited to discriminate the degree to which the QGP medium resolves substructure within a jet. In order to find the optimal grooming strategy, we explore different cuts in the Lund plane that allow for a clear identification of the regions of Soft Drop phase space that enhance the differences in the jet substructure between jets in vacuum and quenched jets. Comparison with present data seems to disfavor an "infinite resolution length", which is to say the hypothesis that the medium interacts with the jet as if it were a single energetic colored object. Our analysis indicates that as the precision of experimental measurements of jet substructure observables and the control over uncertainties in their calculation improves, it will become possible to constrain the value of the resolution length of QGP, in addition to seeing how the substructure of jets is modified via their passage through it.

    hep-phJHEP(2020)·110 citations
20. 20*

    Isospin symmetry breaking effects for the mode $B\to \pi \pi (K)$ in Perturbative QCD

    Gang Lü🇨🇳 · Liang-chen Liu🇨🇳 · Qin-Qin Zhi🇨🇳

    We calculate the direct $CP$ violation for the decay process of $B^0\to {\pi }^0{\pi }^0$, $B^{+}\to {\pi }^0{\pi }^{+}$, $B^0\to K^0{\pi }^0$ and $B^{+}\to K^{+}{\pi }^0$ via isospin symmetry breaking effects from the ${\pi }^0-\eta -{\eta }^{\prime }$ mixing mechanism in perturbative QCD approach. Isospin symmetry breaking originates from the electroweak interaction and the u-d quark mass difference through the strong interaction which are known to be tiny. However, we find that isospin symmetry breaking at the leading order changes the $CP$ violation from the new strong phases. Our calculation results for the $CP$ violation are within or including the range of experimental results. We also compare our results with those from the QCD factorization and the perturbative QCD schemes without regard to isospin symmetry breaking effects.

    hep-ph0 citations
21. 21*

    Minimal inverse seesaw accompanied by Dirac fermionic dark matter

    Pei-Hong Gu🇨🇳

    We present a minimal inverse seesaw mechanism by resorting to a $U(1{)}_{B-L}$ gauge symmetry. In order to cancel the gauge anomalies, we introduce seven neutral fermions among which four participate in the inverse seesaw to induce two nonzero neutrino mass eigenvalues, two forms a stable Dirac fermion to become a dark matter, while the last one keeps massless but decouples early. In this inverse seesaw, two neutral fermions are the usual right-handed neutrinos while the other two have a small Majorana mass term. An additional seesaw mechanism for generating these small Majorana masses also explains the cosmic baryon asymmetry in association with the sphaleron processes.

    hep-phPLB(2020)·4 citations
22. 22*

    Double type-II Dirac seesaw accompanied by Dirac fermionic dark matter

    Pei-Hong Gu🇨🇳

    A TeV-scale Higgs doublet with a small mixing to the standard model Higgs doublet can have the sizable Yukawa couplings to several right-handed neutrinos and the standard model lepton doublets. This provides a testable Dirac neutrino mass generation. We further consider a seesaw mechanism involving a $U(1{)}_{B-L}^{}$ gauge symmetry, which predicts the existence of two right-handed neutrinos and a stable Dirac fermionic dark matter, to simultaneously explain the small mixing between the two Higgs doublets and the generation of the cosmic baryon asymmetry.

    hep-phPLB(2021)·9 citations
23. 23*

    Refined Swampland conjecture in deformed Starobinsky gravity

    Phongpichit Channuie (Walailak U.)🇹🇭

    In order to validate or invalidate a large class of low energy effective theories, the Swampland conjecture has attracted significant attention, recently. It can be stated as inequalities on the potential of a scalar field which is conjectured to satisfy certain constraints. In this work, we discuss the theoretical viability of deformed Starobinky gravity in light of the refined Swampland conjectures. We consider the deformation of the form $f(R)\sim R^{2(1-\alpha )}$ with $\alpha$ being a constant. We then constrain $\alpha$ using the spectral index of curvature perturbation $n_s$ and the tensor-to-scalar ratio $r$. We demonstrate that the model under consideration is in strong tension with the refined swampland conjecture. However, regarding our analysis with proper choices of parameters $a,b=1-a$ and $q$, we discover that the model can always satisfy this new refined swampland conjecture. Therefore, the model might be in landscape since the further refining de Sitter swampland conjecture is satisfied.

    ↳ hep-thgr-qchep-phInt.J.Mod.Phys.D(2022)·15 citations
24. 24*

    Status and Prospects for CPT Tests with the ALPHA Experiment

    T. Friesen (for the ALPHA Collaboration)🇨🇦

    A primary goal of the ALPHA experiment at CERN is to perform precise tests of CPT symmetry. Here, we report on the significant progress made in recent years on antihydrogen spectroscopy and the outlook for the future.

    ↳ hep-exhep-phphysics.atom-ph2 citations
25. 25*

    The dark matter bispectrum from effective viscosity and one-particle irreducible vertices

    Stefan Floerchinger🇩🇪 · Mathias Garny🇩🇪 · Aris Katsis🇬🇷 · Nikolaos Tetradis🇬🇷 · Urs Achim Wiedemann🇨🇭

    Dark matter evolution during the process of cosmological structure formation can be described in terms of a one-particle irreducible effective action at a characteristic scale $k_m$ and a loop expansion below this scale, based on the effective propagators and vertices. We calculate the form of the effective vertices and compute the bispectrum of density perturbations within a one-loop approximation. We find that the effective vertices play a subdominant role as compared to the effective viscosity and sound velocity that modify the (inverse) propagators. For the bispectrum we reproduce the results of standard perturbation theory in the range where it is applicable, and find a slightly improved agreement with N-body simulations at larger wavenumbers.

    ↳ astro-ph.COhep-phJCAP(2019)·9 citations
26. 26*

    Signal detection using biphotons and potential application in axion-like particle search

    Phuong Hoang Le · Binh Xuan Cao🇻🇳

    This paper presents a new optical system for detecting light signals associated with the change in incoming photon number. The system employs quantum correlation of photon pairs created via spontaneous parametric down-conversion (SPDC). The signal, if present, will perturb the flux of the incident photon stream. The perturbed photon stream is first projected through a birefringent crystal where SPDC occurs, converting a single high-energy photon into a pair of low energy photons. The photons in each pair eventually arrive at separate detectors. By examining the biphoton correlation using the probability distribution of the photons at the detectors, which varies depending on the displacement of the main pump photon stream and the change in the number of photons, the small optical displacement of the photon stream and its variance can be determined. The change in incident photon number, in other words, the presence of light signal does not influence the average of the measured optical displacement values. Nevertheless, the change in optical displacement measurement variance when the number of incident photons has changed detects the light signal. This optical setup enables the detection of light signals with low noise and remarkably high precision and sensitivity using quantum correlation. The proposed technique has potential application for axion-like particle search in experimental high energy physics.

    ↳ hep-exhep-phNPB(2020)·1 citation
27. 27*

    Model-independent reconstruction of $f(T)$ gravity from Gaussian Processes

    Yi-Fu Cai🇨🇳 · Martiros Khurshudyan🇨🇳 · Emmanuel N. Saridakis🇬🇷

    We apply Gaussian processes and Hubble function data in $f(T)$ cosmology, to reconstruct for the first time the $f(T)$ form in a model-independent way. In particular, using $H(z)$ datasets coming from cosmic chronometers as well as from the radial BAO method, alongside the latest released local value $H_0=73.52\pm 1.62$ km/s/Mpc, we reconstruct $H(z)$ and its derivatives, resulting eventually in a reconstructed region for $f(T)$, without any assumption. Although the cosmological constant lies in the central part of the reconstructed region, the obtained mean curve follows a quadratic function. Inspired by this we propose a new $f(T)$ parametrization, i.e. $f(T)=-2\Lambda +\xi T^2$, with $\xi$ the sole free parameter that quantifies the deviation from $\Lambda$CDM cosmology. Additionally, we confront three viable one-parameter $f(T)$ models of the literature, which respectively are the power-law, the square-root exponential, and the exponential one, with the reconstructed $f(T)$ region, and then we extract significantly improved constraints for their model parameters, comparing to the constraints that arise from usual observational analysis. Finally, we argue that since we are using the direct Hubble measurements and the local value for $H_0$ in our analysis, with the above reconstruction of $f(T)$, the $H_0$ tension can be efficiently alleviated.

    ↳ astro-ph.COgr-qchep-phhep-thApJ(2020)·141 citations
28. 28*

    Pseudorapidity dependent hydrodynamic response in heavy-ion collisions

    Hui Li🇨🇳 · Li Yan🇨🇳

    We propose a differential hydrodynamic response relation, $V_2(\zeta )=\int d\xi G(\zeta -\xi ){\mathcal{E}}_2(\xi )$, to describe the formation of a pseudorapidity dependent elliptic flow in heavy-ion collisions, in response to a fluctuating three-dimensional initial density profile. By analyzing the medium expansion using event-by-event simulations of 3+1D MUSIC, with initial conditions generated via the AMPT model, the differential response relation is verified. Given the response relation, we are able to separate the two-point correlation of elliptic flow in pseudorapidity into fluid response and two-point correlation of initial eccentricity. The fluid response contains information of the speed of sound and shear viscosity of the medium. From the pseudorapidity dependent response relation, a finite radius of convergence of hydrodynamic gradient expansion is obtained with respect to realistic fluids in heavy-ion collisions.

    ↳ nucl-thhep-phnucl-exPLB(2020)·11 citations
29. 29*

    Primordial fluctuations in heavy-ion collisions

    François Gelis🇫🇷 · Giuliano Giacalone🇫🇷 · Pablo Guerrero-Rodríguez🇪🇸 · Cyrille Marquet🇫🇷 · Jean-Yves Ollitrault🇫🇷

    We present a simple description of the energy density profile created in a nucleus-nucleus collision, motivated by high-energy QCD. The energy density is modeled as the sum of contributions coming from elementary collisions between localized charges and a smooth nucleus. Each of these interactions creates a sharply-peaked source of energy density falling off at large distances like $1/r^2$, corresponding to the two-dimensional Coulomb field of a point charge. Our model reproduces the one-point and two-point functions of the energy density field calculated in the framework of the color glass condensate effective theory, to leading logarithmic accuracy. We apply it to the description of eccentricity fluctuations. Unlike other existing models of initial conditions for heavy-ion collisions, it allows us to reproduce simultaneously the centrality dependence of elliptic and triangular flow.

    ↳ nucl-thhep-phnucl-ex21 citations
30. 30*

    Higgs Vacuum Decay in a Braneworld

    Leopoldo Cuspinera🇬🇧 · Ruth Gregory🇬🇧 · Katie M Marshall🇬🇧 · Ian G Moss🇬🇧

    We examine the effect of large extra dimensions on vacuum decay in the Randall-Sundrum (RS) braneworld paradigm. We assume the scalar field is confined to the brane, and compute the probability for forming an "anti de Sitter" (AdS) bubble inside a critical flat RS brane. We present the first full numerical solutions for the brane instanton considering two test potentials for the scalar field. We explore the geometrical impact of thin and thick bubble walls, and compute the instanton action in a range of cases. We conclude by commenting on a more physically realistic potential relevant for the standard model Higgs. For bubbles with large backreaction, the extra dimension has a dramatic effect on the tunnelling rate, however, for the weakly backreacting bubbles more relevant for realistic Standard Model potentials, the extra dimension has little impact.

    ↳ hep-thhep-phInt.J.Mod.Phys.D(2020)·15 citations
31. 31*

    A link that matters: Towards phenomenological tests of unimodular asymptotic safety

    Gustavo P. de Brito🇧🇷 · Astrid Eichhorn🇩🇰 · Antonio D. Pereira🇧🇷

    Constraining quantum gravity from observations is a challenge. We expand on the idea that the interplay of quantum gravity with matter could be key to meeting this challenge. Thus, we set out to confront different potential candidates for quantum gravity -- unimodular asymptotic safety, Weyl-squared gravity and asymptotically safe gravity -- with constraints arising from demanding an ultraviolet complete Standard Model. Specifically, we show that within approximations, demanding that quantum gravity solves the Landau-pole problems in Abelian gauge couplings and Yukawa couplings strongly constrains the viable gravitational parameter space. In the case of Weyl-squared gravity with a dimensionless gravitational coupling, we also investigate whether the gravitational contribution to beta functions in the matter sector calculated from functional Renormalization Group techniques is universal, by studying the dependence on the regulator, metric field parameterization and choice of gauge.

    ↳ hep-thgr-qchep-phJHEP(2019)·67 citations
32. 32*

    Pion-proton correlation in neutrino interactions on nuclei

    Tejin Cai🇺🇸 · Xianguo Lu🇬🇧 · Daniel Ruterbories🇺🇸

    In neutrino-nucleus interactions, a proton produced with a correlated pion might exhibit a left-right asymmetry relative to the lepton scattering plane even when the pion is absorbed. Absent in other proton production mechanisms, such an asymmetry measured in charged-current pionless production could reveal the details of the absorbed-pion events that are otherwise inaccessible. In this study, we demonstrate the idea of using final-state proton left-right asymmetries to quantify the absorbed-pion event fraction and underlying kinematics. This technique might provide critical information that helps constrain all underlying channels in neutrino-nucleus interactions in the GeV regime.

    ↳ hep-exhep-phnucl-exPRD(2019)·19 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.