Fri·Apr 5, 2019Friday·April 5, 2019

1. 01*

   Constraints on dark matter interactions from the first results of DarkSide-50

   Chun-Yuan Li🇨🇳 · Zong-Guo Si🇨🇳 · Yu-Feng Zhou🇨🇳

   In an extended effective operator framework of isospin violating interactions with light mediators, we investigate the compatibility of the candidate signal of the CDMS-II-Si with the latest constraints from DarkSide-50 and XENON-1T, etc. We show that the constraints from DarkSide-50 which utilizes Argon as the target is complementary to that from XENON-1T which utilizes Xenon. Combining the results of the two experiments, we find that for isospin violating interaction with light mediator there is no parameter space which can be compatible with the positive signals from CDMS-II-Si. As a concrete example of this framework, we investigate the dark photon model in detail. We obtain the combined limits on the dark matter mass $m_{\chi }$, the dark photon mass $m_{A^{\prime }}$, and the kinetic mixing parameter $\epsilon$ in the dark photon model. The DarkSide-50 gives more stringent upper limits in the region of mediator mass from 0.001 to 1 GeV, for $m_{\chi }\lesssim 6$ GeV in the ($m_{A^{\prime }}$,$\epsilon$) plane, and more stringent constraints for $m_{\chi }\lesssim 8$ GeV and $\epsilon \sim 10^{-8}$ in the ($m_{\chi }$,$m_{A^{\prime }}$) plane.

   hep-phNPB(2019)·4 citations
2. 02*

   From the Standard Model towards a Theory of Matter: Quarks

   T. Goldman · G. J. Stephenson · Jr

   We follow the example of Cabibbo by revising the Standard Model (SM) to present a universal mass structure for fermions. A universal Higgs coupling for each species of fundamental fermions moves the SM towards a Theory of Matter, albeit without correctly describing the observed mass spectrum. It exposes a need for a complete Theory of Matter to include components from physics beyond the Standard Model (BSM). Describing the effect of these components phenomenologically provides a means to infer the nature of some of the BSM physics required. Our results also provide constraints on some BSM matrix elements. Here we apply this concept to quarks; the application to leptons will appear in a separate paper. An immediate benefit for theory is the reduction of the largest fine structure constant for the Higgs coupling to fermions by an order of magnitude, which improves the perturbative appearance of the weak interactions. The small mixing of the third generation of each fermion in the fermion families to the others is attributed to the small BSM perturbations that produce the small mass ratio of the lighter generations to the most massive one.

   hep-phnucl-th0 citations
3. 03*

   The NP right-chiral $CC$ coupling constant estimation in neutrino oscillation experiments

   Jacek Syska🇵🇱

   The error probability of the discrimination of the Standard Model (SM) with massive neutrinos and its new physics (NP) model extension in experiments of the muon neutrino oscillation, following the pion decay ${\pi }^{+}\to {\mu }^{+}+{\nu }_{\mu }$, is calculated. The stability of the estimation of the NP charged current coupling constant ${\epsilon }_R$ is analysed and the robustness of this estimation is checked. It is shown that the upper bound on the error probability of erroneous identification of the Standard Model with its NP model extension has reached the significantly small value of approximately $2.3\times 10^{-6}$.

   hep-phInt.J.Theor.Phys.(2021)·0 citations
4. 04*

   Interference-assisted detection of dark photon using atomic transitions

   V.V. Flambaum🇦🇺 · I.B. Samsonov🇦🇺 · H.B. Tran Tan🇦🇺

   Dark photon is a massive vector particle which couples to the physical photon through the kinetic mixing term. Such particles, if exist, are produced in photon beams and, in particular, in laser radiation. Due to the oscillations between the physical photon and the dark photon, the latter may be, in principle, detected in the light-shining-through-a-wall experiment. We propose a variant of this experiment where the detection of dark photons is based on the atomic transitions. The key feature of this scheme is that the detection probability is first order in the coupling constant due to the interference term in the photon and dark photon absorption amplitudes. We expect that such experiment may give new constraints on dark photon coupling constant in the mass region $10^{-3}<m<10^{-2}$ eV.

   hep-phphysics.atom-phPRD(2019)·7 citations
5. 05*

   New approach to the Sivers effect in the collinear twist-3 formalism

   Hongxi Xing🇨🇳 · Shinsuke Yoshida🇨🇳

   The single-transverse spin asymmetry(SSA) for hadron production in the transversely polarized proton scattering receives major contribution from Sivers effect, which can be systematically described within the collinear twist-3 factorization framework in various processes. Conventional method in the evaluation of the Sivers effect known as pole calculation is technically quite different from non-pole calculation which is another method used in evaluating the final state twist-3 effect. In this paper, we extend the non-pole technique to the Sivers effect, and show the consistency with the conventional method through an explicit calculation of $\mathcal{O}({\alpha }_s)$ correction in semi-inclusive deep inelastic scattering. As a result, we clarify that the conventional pole calculation is implicitly using the equation of motion and the Lorentz invariant relations whose importance became widely known in the non-pole calculation. We also clarify some technical advantages in using the new non-pole method.

   hep-phPRD(2019)·12 citations
6. 06*

   Production of doubly heavy baryons via Higgs boson decays

   Juan-Juan Niu🇨🇳 · Lei Guo🇨🇳 · Hong-Hao Ma🇧🇷 · Xing-Gang Wu🇨🇳

   We systematically analyzed the production of semi-inclusive doubly heavy baryons (${\Xi }_{cc}$, ${\Xi }_{bc}$ and ${\Xi }_{bb}$) for the process $H^0\to {\Xi }_{Q{Q}^{\prime }}+\overline{Q^{\prime }}+\bar{Q}$ through four main Higgs decay channels within the framework of non-relativistic QCD. The contributions from the intermediate diquark states, $⟨cc⟩{[}^1{S}_0{]}_6$, $⟨cc⟩{[}^3{S}_1{]}_{\bar{3}}$, $⟨bc⟩{[}^3{S}_1{]}_{\bar{3}/6}$, $⟨bc⟩{[}^1{S}_0{]}_{\bar{3}/6}$, $⟨bb⟩{[}^1{S}_0{]}_6$ and $⟨bb⟩{[}^3{S}_1{]}_{\bar{3}}$, have been taken into consideration. The differential distributions and three main sources of the theoretical uncertainties have been discussed. At the High Luminosity Large Hadron Collider, there will be about 0.43$\times 10^4$ events of ${\Xi }_{cc}$, 6.32$\times 10^4$ events of ${\Xi }_{bc}$ and 0.28$\times 10^4$ events of ${\Xi }_{bb}$ produced per year. There are fewer events produced at the Circular Electron Positron Collider and the International Linear Collider, about $0.26\times 10^2$ events of ${\Xi }_{cc}$, $3.83\times 10^2$ events of ${\Xi }_{bc}$ and $0.17\times 10^2$ events of ${\Xi }_{bb}$ in operation.

   hep-phEPJC(2019)·23 citations
7. 07*

   Decay $X(3872)\to {\pi }^0{\pi }^{+}{\pi }^{-}$ and $S$-wave $D^0{\bar{D}}^0\to {\pi }^{+}{\pi }^{-}$ scattering length

   N.N. Achasov🇷🇺 · G.N. Shestakov🇷🇺

   The isospin-breaking decay $X(3872)\to (D^{\ast }\bar{D}+{\bar{D}}^{\ast }D)\to {\pi }^{0}D\bar{D}\to {\pi }^0{\pi }^{+}{\pi }^{-}$ is discussed. In its amplitude there is a triangle logarithmic singularity, due to which the dominant contribution to $BR(X(3872)\to {\pi }^0{\pi }^{+}{\pi }^{-})$ comes from the production of the ${\pi }^{+}{\pi }^{-}$ system in a narrow interval of the invariant mass $m_{{\pi }^{+}{\pi }^{-}}$ near the value of $2m_{D^0}\approx 3.73$ GeV. The analysis shows that $BR(X(3872)\to {\pi }^0{\pi }^{+}{\pi }^{-})$ can be expected at the level of $10^{-3}$--$10^{-4}$. This estimate includes, in particular, the assumption that the $S$-wave inelastic scattering length $|{\alpha }_{D^0{\bar{D}}^0\to {\pi }^{+}{\pi }^{-}}^{\prime \prime }|\approx 1/(2m_{D^{\ast +}})\approx 0.25\text{mbox}{GeV}^{-1}$.

   hep-phhep-exnucl-thPRD(2019)·15 citations
8. 08*

   Triple-real contribution to the quark beam function in QCD at next-to-next-to-next-to-leading order

   Kirill Melnikov🇩🇪 · Robbert Rietkerk🇩🇪 · Lorenzo Tancredi🇨🇭 · Christopher Wever🇩🇪

   We compute the three-loop master integrals required for the calculation of the triple-real contribution to the N${}^3$LO quark beam function due to the splitting of a quark into a virtual quark and three collinear gluons, $q\to q^{\ast }+ggg$. This provides an important ingredient for the calculation of the leading-color contribution to the quark beam function at N${}^3$LO.

   hep-phJHEP(2019)·24 citations
9. 09*

   Polarization in (quasi-)two-body decays and new physics

   Z. J. Ajaltouni🇫🇷 · E. Di Salvo🇫🇷

   We consider two-body and quasi-two-body decays of the type $f_1\to f_{2}B$, where $f_1$ and $f_2$ are spin-1/2 fermions and $B$ a spin-0 or spin-1 boson. After recalling the non-covariant formalism for decay amplitudes, we derive the expression of the differential decay width and of the polarizations of the final spinning particles, both on- and off-shell. We find an intriguing geometrical interpretation of the results about the polarization. We also illustrate some methods for measuring the polarizations of the resonances and for optimizing data analysis. Then we propose applications to semi-leptonic weak decays, with a major attention to the $T$-odd component of the polarization; this may help to find, simultaneously, possible time-reversal violations and hints to physics beyond the standard model. We suggest also a $CPT$ test. Last, we discuss some $T$-odd observables for the production process of $f_1$ and for the study of the strong final state interactions of non-leptonic decays.

   hep-phEPJC(2019)·4 citations
10. 10*

    Phenomenological Study of Texture Zeros in Lepton Mass Matrices of Minimal Left-Right Symmetric Model

    Happy Borgohain🇮🇳 · Mrinal Kumar Das🇮🇳 · Debasish Borah🇮🇳

    We consider the possibility of texture zeros in lepton mass matrices of the minimal left-right symmetric model (LRSM) where light neutrino mass arises from a combination of type I and type II seesaw mechanisms. Based on the allowed texture zeros in light neutrino mass matrix from neutrino and cosmology data, we make a list of all possible allowed and disallowed texture zeros in Dirac and heavy neutrino mass matrices which appear in type I and type II seesaw terms of LRSM. For the numerical analysis we consider those cases with maximum possible texture zeros in light neutrino mass matrix $M_{\nu }$, Dirac neutrino mass matrix $M_D$, heavy neutrino mass matrix $M_{RR}$ while keeping the determinant of $M_{RR}$ non-vanishing, in order to use the standard type I seesaw formula. The possibility of maximum zeros reduces the free parameters of the model making it more predictive. We then compute the new physics contributions to rare decay processes like neutrinoless double beta decay, charged lepton flavour violation. We find that even for a conservative lower limit on a left-right symmetry scale corresponding to heavy charged gauge boson mass 4.5 TeV, in agreement with collider bounds, for right-handed neutrino masses above 1 GeV, the new physics contributions to these rare decay processes can saturate the corresponding experimental bound.

    hep-phJHEP(2019)·12 citations
11. 11*

    Apparent CPT Violation in Neutrino Oscillation from Dark Non-Standard Interactions

    Shao-Feng Ge🇯🇵 · Hitoshi Murayama🇺🇸

    A natural realization of CPT violation in neutrino oscillation can arise due to the coupling to a light scalar or vector dark matter (DM). The dark non-standard interaction (NSI) is associated with the ${\gamma }_0$ matrix in neutrino's effective propagator and hence corrects the neutrino Hamiltonian as dark matter potential, in the same way as the ordinary matter effect. The effect is, however, inversely proportional to the neutrino energy and hence appears as a correction to the neutrino mass squared. Due to a sign difference in the corrections for neutrino and anti-neutrino modes, the neutrino oscillation receives CPT violation from the dark NSI. Seeing difference in the neutrino and anti-neutrino mass squared differences not necessarily leads to the conclusion of CPT symmetry breaking in the fundamental Lagrangian but can indicate light DM and its coupling with neutrinos.

    hep-phhep-ex37 citations
12. 12*

    Fast-Rolling Relaxion

    Masahiro Ibe🇯🇵 · Yutaro Shoji🇯🇵 · Motoo Suzuki🇯🇵

    We discuss new mechanisms to stop the relaxion field during inflation. They can be realized in a generic model, including the original model but in a quite different parameter region. We consider a fast-rolling relaxion field, which can go over the bumps created by QCD-like dynamics. Then, in one of the mechanisms, we stop it with a parametric resonance of the Higgs field. The mechanisms are free from a super-Planckian field excursion or a gigantic number of e-folds of inflation. The relaxion has a mass around the weak scale and mixes with the Higgs boson, which enhances the testability of our mechanisms.

    hep-phJHEP(2019)·17 citations
13. 13*

    The Minimal Simple Composite Higgs Model

    Leandro Da Rold (1 and 2)🇦🇷 · Alejo N. Rossia (2 and 3) ((1) CONICET, (2) Instituto Balseiro, (3) DESY)🇩🇪

    Most of the analysis of composite Higgs have focussed on the Minimal Composite Higgs Model, based on the coset SO(5)$\times$U(1)${}_X$/SO(4)$\times$U(1)${}_X$. We consider a model based on the coset of simple groups SO(7)/SO(6), with SO(4)$\times$U(1)${}_X$ embedded into SO(6). This extension of the minimal model leads to a new complex pNGB that has hypercharge and is a singlet of SU(2)${}_L$, with properties mostly determined by the pattern of symmetry breaking and a mass of order TeV. Composite electroweak unification also leads to new bosonic and fermion resonances with exotic charges, not present in the minimal model. The lightest of these resonances is stable, and in some cases could provide candidates for dark matter. A new rich phenomenology is expected at LHC.

    hep-phJHEP(2019)·20 citations
14. 14*

    UV contributions to energy of a static quark-antiquark pair in large ${\beta }_0$ approximation

    Yuuki Hayashi🇯🇵 · Yukinari Sumino🇯🇵

    The total energy of a static quark-antiquark pair $E_{\mathrm{tot}}(r)=2m_{\mathrm{pole}}+V_{\mathrm{QCD}}(r)$ is known to be predictable up to $\mathcal{O}({\Lambda }_{\mathrm{QCD}}^3{r}^2)$ and $\mathcal{O}(\frac{{\Lambda }_{\mathrm{QCD}}^3}{{\overline{m}}^2})$ renormalon uncertainties in the large-${\beta }_0$ approximation, after canceling $\mathcal{O}({\Lambda }_{\mathrm{QCD}})$ renormalons. We compute the predictable part (genuine UV part) in terms of the $\overline{\mathrm{MS}}$ mass $\overline{m}$, extending a recently-proposed method which conforms with OPE. In particular the $r$-independent part is determined. The result would help understanding the nature of $E_{\mathrm{tot}}(r)$ in the context of OPE with renormalon subtraction.

    hep-phPLB(2019)·5 citations
15. 15*

    Pion-photon transition form factor in QCD. Theoretical predictions and topology-based data analysis

    N. G. Stefanis🇩🇪

    We discuss the evaluation of the transition form factor (TFF) $F^{\gamma \ast \gamma {\pi }^0}(Q^2)$ by means of QCD theory and by state-space reconstruction from topological data analysis. We first calculate this quantity in terms of quark-gluon interactions using light cone sum rules (LCSRs). The spectral density includes radiative corrections in leading, next-to-leading, and next-to-next-to-leading-order of perturbative QCD. Besides, it takes into account the twist-four and twist-six terms. The hard-scattering part in the LCSR is convoluted with various pion distribution amplitudes with different morphologies in order to obtain a wide range of predictions for the form factor, including two-loop evolution which accounts for heavy-quark thresholds. We then use nonlinear time series analysis to extract information on the long-term $Q^2$ behavior of the measured scaled form factor in terms of state-space attractors embedded in ${\mathbb{R}}^3$. These are reconstructed by applying the Packard-Takens method of delays to appropriate samplings of the data obtained in the CLEO, \textit{BABAR}, and Belle single-tagged $e^{+}{e}^{-}\to e^{+}{e}^{-}{\pi }^0$ experiments. The corresponding lag plots show an aggregation of states around the value $Q^2{F}^{\gamma \ast \gamma {\pi }^0}(Q^2)\approx 0.165\pm 0.005$ GeV pertaining to the momentum interval $Q^2\in [9-11]$~GeV${}^2$. We argue that this attractor portrait is a transient precursor of a distribution of states peaking closer to the asymptotic limit $Q^2{F}^{\gamma \ast \gamma {\pi }^0}(Q^2\to \infty )=\sqrt{2}{f}_{\pi }$~GeV. More data with a regular increment of 1~GeV${}^2$ in the range between 10 and 25~GeV${}^2$ would be sufficient to faithfully determine the terminal portrait of the attractor.

    hep-phhep-exhep-latphysics.data-an7 citations
16. 16*

    Doubly heavy $QQ$ tetraquarks

    Michal Praszalowicz🇵🇱

    With the discovery of a doubly charmed ${\Xi }_{cc}$ baryon a somewhat forgotten issue of tetraquarks containing two heavy and two light (anti) quarks, ${\mathcal{T}}_{QQ}$, triggered theorist's interest. We discuss quark model estimates of ${\mathcal{T}}_{QQ}$ masses and such objects including a model where the light sector is treated as a soliton. We show that this model has different large $N_c$ limit than other approaches.

    hep-phActa Phys.Polon.Supp.(2020)·4 citations
17. 17*

    Proton Spin Structure at Small-$x$

    Renaud Boussarie🇺🇸 · Yoshitaka Hatta🇺🇸 · Feng Yuan🇺🇸

    We generalize the Bartels-Ermolaev-Ryskin approach for the $g_1$ structure function at small-$x$ to determine the small-$x$ asymptotic behavior of the orbital angular momentum distributions in QCD. We present an exact analytical solution of the evolution equation in the double logarithmic approximation and discuss its implications for the proton spin problem.

    hep-phPLB(2019)·61 citations
18. 18*

    Gravitational waves from the minimal gauged $U(1{)}_{B-L}$ model

    Taiki Hasegawa🇯🇵 · Nobuchika Okada🇺🇸 · Osamu Seto🇯🇵

    An additional $U(1)$ gauge interaction is one of promising extensions of the standard model of particle physics. Among others, the $U(1{)}_{B-L}$ gauge symmetry is particularly interesting because it addresses the origin of Majorana masses of right-handed neutrinos, which naturally leads to tiny light neutrino masses through the seesaw mechanism. We show that, based on the minimal $U(1{)}_{B-L}$ model, the symmetry breaking of the extra $U(1)$ gauge symmetry with its minimal Higgs sector in the early Universe can exhibit the first-order phase transition and hence generate a large enough amplitude of stochastic gravitational wave radiation which is detectable in future experiments.

    hep-phastro-ph.COPRD(2019)·97 citations
19. 19*

    Testing the strength of the ${\text{U}}_A(1)$ anomaly at the chiral phase transition in two-flavour QCD

    Bastian B. Brandt🇩🇪 · Marco Cè🇩🇪 · Anthony Francis🇨🇭 · Tim Harris🇮🇹 · Harvey B. Meyer🇩🇪 · Owe Philipsen🇩🇪 · Hartmut Wittig🇩🇪

    We study the thermal transition of QCD with two degenerate light flavours by lattice simulations using $\mathcal{O}(a)$-improved Wilson quarks. Particular emphasis lies on the pattern of chiral symmetry restoration, which we probe via the static screening correlators. On $32^3$ volumes we observe that the screening masses in transverse iso-vector vector and axial-vector channels become degenerate at the transition temperature. The splitting between the screening masses in iso-vector scalar and pseudoscalar channels is strongly reduced compared to the splitting at zero temperature and is actually consistent with zero within uncertainties. In this proceedings article we extend our studies to matrix elements and iso-singlet correlation functions. Furthermore, we present results on larger volumes, including first results at the physical pion mass.

    ↳ hep-lathep-phnucl-thPoS(2019)·13 citations
20. 20*

    Shear viscosity of classical fields in scalar theory

    Hidefumi Matsuda🇯🇵 · Teiji Kunihiro🇯🇵 · Akira Ohnishi🇯🇵 · Toru T. Takahashi🇯🇵

    We investigate the shear viscosity of massless classical scalar fields in the ${\varphi }^4$ theory on a lattice by using the Green-Kubo formula. Based on the scaling property of the classical field, the shear viscosity is represented using a scaling function. Equilibrium expectation value of the time-correlation function of the energy-momentum tensor is evaluated as the ensemble average of the classical field configurations, whose time evolution is obtained by solving the classical equation of motion starting from the initial condition in thermal equilibrium. It is found that there are two distinct damping time scales in the time-correlation function, which is found to show damped oscillation behavior in the early stage around a slow monotonous decay with an exponential form, and the slow decay part is found to dominate the shear viscosity in the massless classical field theory. This kind of slow decay is also known to exist in the molecular dynamics simulation, then it may be a generic feature of dense matter.

    ↳ cond-mat.stat-mechhep-phnucl-thPTEP(2020)·2 citations
21. 21*

    The DAMPE excess and gamma-ray constraints

    Konstantin Belotsky🇷🇺 · Airat Kamaletdinov🇷🇺 · Maxim Laletin🇧🇪 · Maxim Solovyov🇷🇺

    The direct measurements of the cosmic electron-positron spectrum around 1 TeV made by DAMPE have induced many theoretical speculations about possible excesses in the data above the standard astrophysical predictions that might have the dark matter (DM) origin. These attempts mainly fall into two categories: i) DM annihilation (or decay) in the Galactic halo producing the broad spectrum excess; ii) DM annihilation in the nearby compact subhalo producing the sharp peak at 1.4 TeV. We investigate the gamma-ray emission accompanying $e^{+}{e}^{-}$ production in DM annihilation, as well as various theoretical means to suppress the prompt radiation, such as specific interaction vertices or multi-cascade modes, and conclude that these attempts are in tension with various gamma-ray observations. We show that the DM explanations of the broad spectrum excess tend to contradict the diffuse isotropic gamma-ray background (IGRB), measured by Fermi-LAT, while the nearby subhalo scenario is constrained by nonobservation in the surveys, performed by Fermi-LAT, MAGIC and HESS. We also briefly review other types of gamma-ray constraints, which seem to rule out the DM interpretations of the DAMPE broad spectrum excess as well.

    ↳ astro-ph.HEastro-ph.COhep-phPhys.Dark Univ.(2019)·21 citations
22. 22*

    Implications of the possible 21-cm line excess at cosmic dawn on dynamics of interacting dark energy

    Chunlong Li🇨🇳 · Xin Ren🇨🇳 · Martiros Khurshudyan🇨🇳 · Yi-Fu Cai🇨🇳

    In this paper we study implications of the possible excess of 21-cm line global signal at the epoch of cosmic dawn on the evolutions of a class of dynamically interacting dark energy (IDE) models. We firstly summarize two dynamical mechanisms in which different background evolutions can exert considerable effects on the 21-cm line global signal. One is the decoupling time of Compton scattering heating, the other stems from the direct change of optical depth due to the different expansion rate of the Universe. After that, we investigate the IDE models to illustrate the tension between the results of Experiment to Detect the Global Epoch of reionization Signature (EDGES) and other experiments. To apply the analyses of these two mechanisms to IDE models, we find that only the optical depth can be significantly changed. Accordingly, in order to relieve the tension by including the effects of the decoupling time of Compton scattering heating, we deduce a possible evolution form for the Hubble parameter within IDE that begins at an early stage around $z\sim 100$ and then smoothly evolves to a value at $z\sim 17$ which is smaller than that obtained in the standard paradigm. Eventually, we fulfill this scenario by adding an early dark energy dominated stage to the cosmological paradigm described by IDE models, which can alleviate the tension between EDGES and other cosmological observations but cannot completely solve it.

    ↳ astro-ph.COgr-qchep-phhep-thPLB(2020)·64 citations
23. 23*

    General modal estimation for cross-bispectra

    Maresuke Shiraishi🇯🇵 · Michele Liguori🇮🇹 · James R. Fergusson🇬🇧 · E.P.S. Shellard🇬🇧

    We describe a fast, optimal estimator for measuring angular bispectra between two correlated weakly non-Gaussian fields ($Y$ and $Z$) from observational datasets, based on a separable modal bispectrum expansion. Our methodology is applicable to (1) any shape of the input theoretical bispectrum templates (factorizable or not), (2) both even and odd ${\ell }_1+{\ell }_2+{\ell }_3$ multipole domains and (3) both amplitude ($f_{\mathrm{NL}})$ bispectrum estimation and full bispectrum reconstruction, considering either joint estimation of ($YYY$, $ZZZ$, $YYZ$ and $ZZY$) shapes, or independent estimation of auto-bispectra ($YYY$ or $ZZZ$) and cross-bispectra ($YYZ$ or $ZZY$); hence, it has quite high versatility. The methodology described here was implemented and used for the official analysis of temperature and polarization cosmic microwave background maps from the $Planck$ satellite.

    ↳ astro-ph.COgr-qchep-phJCAP(2019)·7 citations
24. 24*

    Confinement of fermions in tachyon matter

    Adamu Issifu🇧🇷 · Francisco A. Brito🇧🇷

    In this paper we develop a phenomenological model inspired by QCD that mimics QCD theory. We use gauge theory in color dielectric medium ($G(\varphi )$) coupled with fermion fields to produce scalar and vector confinement in chromoelectric flux tube scenario. Abelian theory will be used to approximate the non-Abelian QCD theory in a consistent manner. We will calculate vector and scalar glueballs and compare the result to the existing simulation and experimental results and projections. The QCD-like vacuum associated with the model will be calculated and its behavior studied relative to changing quark masses. We will also comment on the relationship between tachyon condensation, dual Higgs mechanism, QCD monopole condensation and their association with confinement. The behavior of the QCD string tension obtained from the vector potential of the model will be studied to establish vector dominance in confinement theories.

    ↳ hep-thhep-phAdv.High Energy Phys.(2020)·5 citations
25. 25*

    Bottom-up Acceleration of Ultra-High-Energy Cosmic Rays in the Jets of Active Galactic Nuclei

    Rostom Mbarek🇺🇸 · Damiano Caprioli (University of Chicago)🇺🇸

    It has been proposed that Ultra-High-Energy Cosmic Rays (UHECRs) up to $10^{20}$eV could be produced in the relativistic jets of powerful Active Galactic Nuclei (AGNs) via a one-shot reacceleration of lower-energy CRs produced in supernova remnants (the $\text{espresso}$ mechanism). We test this theory by propagating particles in realistic 3D magneto-hydrodynamic simulations of ultra-relativistic jets and find that about $10\%$ of the CRs entering the jet are boosted by at least a factor of $\sim {\Gamma }^2$ in energy, where $\Gamma$ is the jet's effective Lorentz factor, in agreement with the analytical expectations. Furthermore, about $0.1\%$ of the CRs undergo two or more shots and achieve boosts well in excess of ${\Gamma }^2$. Particles are typically accelerated up to the Hillas limit, suggesting that the $\text{espresso}$ mechanism may promote galactic-like CRs to UHECRs even in AGN jets with moderate Lorentz factors, and not in powerful blazars only. Finally, we find that the sign of the toroidal magnetic field in the jet and in the cocoon controls the angular distribution of the reaccelerated particles, leading to a UHECR emission that may be either quasi-isotropic or beamed along the jet axis. These findings strongly support the idea that $\text{espresso}$ acceleration in AGN jets can account for the UHECR spectra, chemical composition, and arrival directions measured by Auger and Telescope Array.

    ↳ astro-ph.HEhep-phApJ·46 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.