Tue·Jun 25, 2019Tuesday·June 25, 2019

1. 01*

   Perspectives of photon physics at future colliders

   M. Klasen🇩🇪

   We review current results on physics with photons at the LHC and discuss realistic perspectives of photon physics at future colliders. In particular, we focus on Standard Model (SM) measurements with photons at the upcoming high-luminosity and a possible high-energy LHC as well as jet measurements at an Electron-Ion Collider (EIC) to be constructed either at BNL or at JLAB and their potential to constrain nuclear parton densities. We also discuss future searches for physics beyond the SM with photons in the high-luminosity phase of the LHC.

   hep-phhep-exnucl-exnucl-thFrascati Phys.Ser.(2019)·3 citations
2. 02*

   Probing the anomalous electromagnetic dipole moments of the top quark in $\gamma p$ collision at the LHC, the HL-LHC and the HE-LHC

   M. Koksal🇹🇷

   The determination of the electromagnetic dipole moments of the top quark is one of the most important goals of the top quark physics program in the collider experiments. For this reason, the top quark pair production to investigate the sensitivity on the electric and magnetic dipole moments of the top quark via the process $pp\to p\gamma p\to pt\bar{t}X$ at the Large Hadron Collider (LHC), the High-Luminosity Large Hadron Collider (HL-LHC) and High-Energy Large Hadron Collider (HE-LHC) is discussed. We apply pure leptonic and semileptonic decays for top quark pair production in the final state. Moreover, we consider systematic uncertainties of $0,3\%$ and $5\%$. The best limits obtained from the process $pp\to p\gamma p\to pt\bar{t}X$ on the anomalous $a_A$ and $a_V$ couplings are $|a_A|=0.0200$ and $a_V=[-0.9959;0.0003]$. Thus, our results indicate that the process $pp\to p\gamma p\to pt\bar{t}X$ is a very good perspective to probe the electric and magnetic dipole moments of the top quark at the HL-LHC and the HE-LHC.

   hep-phNPB(2020)·7 citations
3. 03*

   Holographic QCD predictions for rare B decays

   Mohammad Ahmady🇨🇦 · Ruben Sandapen🇨🇦

   Light-front wavefunctions obtained from holographic light-front QCD are used to obtain the distributions amplitudes for $K^{\ast }$ vector meson. Consequently, alternate predictions for rare B transitions to $K^{\ast }$ form factors are presented. In this talk, I compare our results for some rare B decay channels to those obtained from QCD sum rules and available experimental data.

   hep-ph0 citations
4. 04*

   Neutrino flavor oscillations and spin rotation in matter and electromagnetic field

   A. V. Chukhnova🇷🇺 · A. E. Lobanov🇷🇺

   We obtain a relativistically covariant wave equation for neutrinos in dense matter and electromagnetic field, which describes both flavor oscillations and neutrino spin rotation. Using this equation we construct a quasi-classical theory of these phenomena. We obtain the probabilities of arbitrary spin-flavor transitions assuming the external conditions to be constant. We demonstrate that the resonance behavior of the transition probabilities is possible only when the neutrino flavor states cannot be described as superpositions of the mass eigenstates. We discover that a resonance, which is similar to the Mikheev-Smirnov-Wolfenstein resonance, takes place for neutrinos in magnetic field due to the transition magnetic moments. This resonance gives an opportunity to determine, whether neutrinos are Dirac or Majorana particles.

   hep-phhep-thPRD(2020)·20 citations
5. 05*

   Quasi-two-body decays $B_{(s)}\to P{D}_0^{\ast }(2400)\to PD\pi$ in the perturbative QCD approach

   Bo-Yan Cui🇨🇳 · Ying-Ying Fan🇨🇳 · Fu-Hu Liu🇨🇳 · Wen-Fei Wang🇨🇳

   We study the quasi-two-body decays $B\to P{D}_0^{\ast }(2400)\to PD\pi$ with $P=(\pi ,K,\eta ,{\eta }^{\prime })$ in the perturbative QCD factorization approach. The predicted branching fractions for the considered decays are in the range of $10^{-9}$-$10^{-4}$. The strong Cabibbo-Kobayashi-Maskawa (CKM) suppression factor $R_{CKM}\approx {\lambda }^4({\bar{\rho }}^2+{\bar{\eta }}^2)\approx 3\times 10^{-4}$ results in the great difference of the branching ratios for the decays with $D_0^{\ast }$ and ${\bar{D}}_0^{\ast }$ as the intermediate states. The ratio $R_{{\bar{D}}_0^{\ast 0}}$ between the decays $B^0\to {\bar{D}}_0^{\ast 0}{K}^0\to D^{-}{\pi }^{+}{K}^0$ and $B^0\to {\bar{D}}_0^{\ast 0}{\pi }^0\to D^{-}{\pi }^{+}{\pi }^0$ is about $0.091_{-0.005}^{+0.003}$, consistent with the flavour-$SU$(3) symmetry result. The ratio for the branching fractions is found to be $1.10_{-0.02}^{+0.05}$ between $\mathcal{B}(B_s^0\to D_0^{\ast +}{K}^{-}\to D^0{\pi }^{+}{K}^{-})$ and $\mathcal{B}(B^0\to D_0^{\ast +}{\pi }^{-}\to D^0{\pi }^{+}{\pi }^{-})$ and to be $1.03_{-0.07}^{+0.06}$ between $\mathcal{B}(B_s^0\to {\bar{D}}_0^{\ast 0}{\bar{K}}^0\to D^{-}{\pi }^{+}{\bar{K}}^0)$ and $2\mathcal{B}(B^0\to {\bar{D}}_0^{\ast 0}{\pi }^0\to D^{-}{\pi }^{+}{\pi }^0)$. The predictions in this work can be tested by the future experiments.

   hep-phPRD(2019)·10 citations
6. 06*

   Exploring CP-Violating heavy neutrino oscillations in rare tau decays at Belle II

   Sebastian Tapia🇺🇸 · Jilberto Zamora-Saá🇨🇱

   In this work, we study the lepton number violating tau decays via two intermediate on-shell Majorana neutrinos $N_j$ into two charged pions, and a charged lepton ${\tau }^{\pm }\to {\pi }^{\pm }{N}_j\to {\pi }^{\pm }{\pi }^{\pm }{\ell }^{\mp }$. We consider the scenario where the heavy neutrino masses are within $0.5$ GeV $\le M_N\le 1.5$ GeV. We evaluated the possibility to measure the modulation of the decay width along the detector length for these processes at taus factories, such as Belle II. We study some realistic conditions which could lead to the observation of this phenomenon at futures $\tau$'s factories.

   hep-phNPB(2020)·24 citations
7. 07*

   Neutrino spin-flavor oscillations in solar environment

   Sandeep Joshi🇮🇳 · Sudhir R. Jain🇮🇳

   We study the phenomenon of neutrino spin-flavor oscillations due to solar magnetic fields. This allows us to examine how significantly the electron neutrinos produced in the solar interior undergo a resonant spin-flavor conversion. We construct analytical models for the solar magnetic field in all the three regions of the Sun. Neutrino spin-flavor oscillations in these magnetic fields are examined by studying the level crossing phenomenon and comparing the two cases of zero and non-zero vacuum mixing respectively. Results from the Borexino experiment are used to place an upper limit on the magnetic field in the solar core. Related phenomena such as effects of matter on neutrino spin transitions and differences between Dirac and Majorana transitions in the solar magnetic fields are also discussed.

   hep-phastro-ph.SRRes.Astron.Astrophys.(2020)·11 citations
8. 08*

   Meson-Hybrid Mixing in Vector ($1^{--}$) and Axial Vector ($1^{++}$) Charmonium

   D. Harnett🇨🇦 · A. Palameta🇨🇦 · J. Ho🇨🇦 · T. G. Steele🇨🇦

   We study mixing between conventional and hybrid mesons in vector and axial vector charmonium using QCD Laplace sum-rules. We compute meson-hybrid cross correlators within the operator product expansion, taking into account condensate contributions up to and including those of dimension-six as well as composite operator renormalization-induced diagrams. Using measured masses of charmonium-like states as input, we probe known resonances for nonzero coupling to both conventional and hybrid meson currents, a signal for meson-hybrid mixing.

   hep-ph0 citations
9. 09*

   Top condensation model: a step towards the correct prediction of the Higgs mass

   A.A. Osipov🇷🇺 · B. Hiller🇵🇹 · A.H. Blin🇵🇹 · F. Palanca🇵🇹 · J. Moreira🇵🇹 · M. Sampaio🇧🇷

   A realization of the composite Higgs scenario in the context of the effective model with the $SU(2{)}_L\times U(1{)}_R$ symmetric four-Fermi interactions proposed by Miransky, Tanabashi and Yamawaki is studied. The model implements Nambu's mechanism of dynamical electroweak symmetry breaking leading to the formation of $\bar{t}t$ and $\bar{b}b$ quark condensates. We explore the vacuum structure and spectrum of the model by using the Schwinger proper-time method. As a direct consequence of this mechanism, the Higgs acquires a mass in accord with its experimental value. The present prediction essentially differs from the known overestimated value, $m_{\chi }=2m_t$, making more favourable the top condensation scenario presented here. The mass formulas for the members of the second Higgs doublet are also obtained. The Nambu sum rule is discussed. It is shown that the anomalous $U(1{)}_A$ symmetry breaking modifies this rule at next to leading order in $1/N_c$.

   hep-phEPJC(2020)·6 citations
10. 10*

    BFKL equation in the next-to-leading order: solution at large impact parameters

    Carlos Contreras (UTFSM)🇨🇱 · Eugene Levin (Tel Aviv U,/UTFSM)🇮🇱 · Rodrigo Meneses (Valparaiso U.)🇨🇱

    In this paper, we show (i) that the NLO corrections do not change the power-like decrease of the scattering amplitude at large impact parameter (b^2 \,>\,r^2 \exp\left( 2\bar(\alpha}_S \eta(1 + 4 \bar{\alpha}_S)\right), where $r$ denotes the size of scattering dipole and $\eta =\ln (1/x_{Bj})$ for DIS), and, therefore, they do not resolve the inconsistency with unitarity; and (ii) they lead to an oscillating behaviour of the scattering amplitude atlarge $b$, in direct contradiction with the unitarity constraints. However, from the more practical point of view, the NLO estimates give a faster decrease of the scattering amplitude as a function of $b$, and could be very useful for description of the experimental data. It turns out, that in a limited range of $b$, the NLO corrections generates the fast decrease of the scattering amplitude with $b$, which can be parameterized as $N\propto \exp (-\mu b)$ with $\mu \propto 1/r$ in accord with the numerical estimates in Ref.[1].

    hep-phEPJC(2019)·9 citations
11. 11*

    Singlet-Doublet Dirac Dark Matter and Neutrino Masses

    Diego Restrepo🇨🇴 · Andrés Rivera🇨🇴 · Walter Tangarife🇺🇸

    We examine an extension of the Standard Model that addresses the dark matter puzzle and generates Dirac neutrinos masses through the radiative seesaw mechanism. The new field content includes a scalar field that plays an important role in setting the relic abundance of dark matter. We analyze the phenomenology in the light of direct, indirect, and collider searches of dark matter. In this framework, the dark matter candidate is a Dirac particle that is a mixture of new singlet-doublet fields with mass $m_{{\chi }_1^0}\lesssim 1.1\text{TeV}$. We find that the allowed parameter space of this model is broader than the well-known Majorana dark matter scenario.

    hep-phPRD(2019)·24 citations
12. 12*

    X(3872) in an unquenched quark model

    Yue Tan🇨🇳 · Jialun Ping🇨🇳

    In this paper, we calculate mass and probability fractions of meson-meson components of $X(3872)$ in an unquenched quark model. Different from most of other unquenched quark models, the quark pairs creation operator from ${}^3{P}_0$ is modified by considering effects of the created quark pair energy and separation between the created quark pair and the valence quark-pair. In the calculation, all the wavefunctions of mesons and the relative motion between two mesons are obtained by solving the corresponding Schrödinger equation with the help of gaussian expansion method. The multi-channel coupling of quark-antiquark state with possible meson-meson states are performed. The results show that the $X(3872)$ can be described as a mixing state of dominant charmonium state (70\%) and meson-meson components (30\%).

    hep-phPRD(2019)·23 citations
13. 13*

    Implications of Four-Top and Top-Pair Studies on Triple-Top Production

    Wei-Shu Hou🇹🇼 · Masaya Kohda🇹🇼 · Tanmoy Modak🇹🇼

    Multi-top quark production is a staple program at the LHC. Single-top and $t\bar{t}$ productions are studied extensively, while current efforts are zooming in on four-top search, where the Standard Model (SM) cross section is at $\mathcal{O}(10)$ fb. In contrast, only at the fb level in SM, triple-top production has not been targeted for study so far. But such a small cross section makes it a unique probe for New Physics. Without the usual discrete $Z_2$ symmetry, the general two Higgs doublet model (g2HDM) can naturally raise the triple-top production to pb level. We illustrate how certain signal regions of four-top search can be utilized to constrain triple-top production, but urge a dedicated search. As an aside, we note that the CMS study at 13 TeV of scalar $t\bar{t}$ resonance interfering with QCD production background indicate some activity at 400 GeV. We comment that this could be explained in principle in g2HDM via the extra top Yukawa coupling.

    hep-phhep-exPLB(2019)·28 citations
14. 14*

    Dissociation of Nucleon and Heavy-Baryon in an Anisotropic Hot and Dense QCD Media Using Nikiforov-Uvarov Method

    M. Abu-Shady🇪🇬 · A. N. Ikot🇳🇬

    By using the Nikiforov-Uvarov method, the hyper-radial Schrodinger equation is analytically solved, in which the real modified potential is employed at finite temperature and baryon chemical potential. The eigenvalue of energy and corresponding wave function are obtained in the isotropic and anisotropic media in hot and dense media. The present results show that the binding energy of nucleon and some heavy baryon decrease strongly in hot medium and decreases slightly with increasing baryon chemical potential. In addition, binding energy for each baryon is more bound in an anisotropic medium in comparison with its value in an isotropic medium. The dissociation of temperature of each baryon is above a critical temperature and it increases in the anisotropic medium. The dissociation of temperature is slightly decreased in the hot medium when the baryon of chemical potential is considered. A comparison is studied with the available studies. We conclude that the present study provides a good description of the nucleon and some heavy baryon in hot and dense media in the isotropic and anisotropic systems.

    hep-phnucl-thEur.Phys.J.Plus(2020)·5 citations
15. 15*

    Dark matter as Planck relics without too exotic hypotheses

    Aurélien Barrau🇫🇷 · Killian Martineau🇫🇷 · Flora Moulin🇫🇷 · Jean-Frédéric Ngono🇫🇷

    The idea that dark matter could be made of stable relics of microscopic black holes is not new. In this article, we revisit this hypothesis, focusing on the creation of black holes by the scattering of trans-Planckian particles in the early Universe. The only new physics required in this approach is an unusually high-energy scale for inflation. We show that dark matter emerges naturally and we study the question of fine-tuning. We finally give some lines of thoughts for a possible detection.

    hep-phastro-ph.COgr-qcPRD(2019)·26 citations
16. 16*

    Excited Quarks Production at FCC and S$pp$C $pp$ Colliders

    Mehmet Sahin🇹🇷 · Güral Aydin🇹🇷 · Yusuf Oguzhan Günaydin🇹🇷

    Potential discovery, observation and exclusion limits of excited $u$ and $d$ quarks with gamma+jet final state are researched at the multi-TeV scale colliders, FCC and S$pp$C in this work. Both colliders, FCC and S$pp$C, show that excited $u$ and $d$ quarks could be discovered up to 42.1 TeV and 55.2 TeV for $u^{\star }$, 30.3 TeV and 39.4 TeV for $d^{\star }$ and 42.3 TeV and 55.5 TeV mass values for degenerate case (m${}_{u^{\star }}$ = m${}_{d^{\star }}$), respectively. Determination of excited quarks compositeness scale is examined, which will be up to multi-PeV level. Beside these analysis, free parameters ($f_s,f\text{and}{f}^{\prime }$) are scanned from around 0.1 up to 1 that show excited quark could be discovered at dozens of TeV with even coupling constants under 0.1.

    hep-phInt.J.Mod.Phys.A(2019)·2 citations
17. 17*

    Measurement of the neutron lifetime and inverse quantum Zeno effect

    Francesco Giacosa🇵🇱 · Giuseppe Pagliara🇮🇹

    Quantum mechanics predicts that the decay rate of unstable systems could be effectively modified by the process of the measurement of the survival probability. Depending on the intrinsic properties of the unstable system and the experimental setup for the observation, one could obtain the so called (direct) quantum Zeno and inverse quantum Zeno effects corresponding to a slowing down or a speeding up of the decay, respectively. We argue that the inverse quantum Zeno effect is in principle detectable at a percent level for the neutron decay in experiments with trapped ultracold neutrons. Conversely, this effect is basically undetectable in experiments in which the neutron lifetime is measured by measuring the decays of beams of neutrons. As a test of our claim, we propose a simple qualitative correlation between the number of neutrons in the trap and the neutron lifetime: the larger the number, the faster the decay. Finally we discuss also the presently available measurements of the neutron lifetime and address the issue of the possible discrepancy that has been reported among the results obtained by the different experimental techniques.

    hep-phquant-phPRD(2020)·17 citations
18. 18*

    Prompt $J/\psi$-pair production at the LHC: impact of loop-induced contributions and of the colour-octet mechanism

    Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇫🇷 · Nodoka Yamanaka🇫🇷 · Yu-Jie Zhang🇨🇳

    Prompt double-$J/\psi$ production at high-energy hadron colliders can be considered as a golden channel to probe double parton scatterings (DPS) --in particular to study gluon-gluon correlations inside the proton-- and, at the same time, to measure the distribution of linearly-polarised gluons inside the proton. Such studies however require a good control of both single and DPS in the respective regions where they are carried out. In this context, we have critically examined two mechanisms of single parton scatterings (SPS) that may be kinematically enhanced where DPS are thought to be dominant, even though they are either at higher orders in the strong-coupling or velocity expansion. First, we have considered a gauge-invariant and infrared-safe subset of the loop-induced contribution via Colour-Singlet (CS) transitions. We have found it to become the leading CS SPS contributions at large rapidity separation, yet too small to account for the data without invoking the presence of DPS yields. Second, we have surveyed the possible Colour-Octet (CO) contributions using both old and up-to-date non-perturbative long distance matrix elements (LDMEs). We have found that the pure CO yields crucially depend on the LDMEs. Among all the LDMEs we used, only two result into a visible modification of the NRQCD (CS+CO) yield, but only in two kinematical distributions measured by ATLAS, those of the rapidity separation and of the pair invariant mass. These modifications however do not impact the control region used for their DPS study.

    hep-phhep-exnucl-exnucl-thEPJC(2019)·29 citations
19. 19*

    Efficient interpolation and evolution of parton distribution functions

    Riccardo Nagar🇩🇪

    We present an efficient numerical solution of the DGLAP equations for single and double parton distribution functions (PDFs and DPDs), based on the Chebyshev interpolation of these functions. For PDF evolution, our method allows for a higher numerical accuracy using a considerably smaller number of grid points compared to other methods. The DPD evolution is realized using an affordable number of grid points, and allows for two independent renormalization scales for the two partons. Both methods include NNLO DGLAP kernels and flavor matching.

    hep-phPoS(2019)·6 citations
20. 20*

    Full next-to-leading-order calculations of Higgs boson decay rates in models with non-minimal scalar sectors

    Shinya Kanemura🇯🇵 · Mariko Kikuchi🇯🇵 · Kentarou Mawatari🇯🇵 · Kodai Sakurai🇯🇵 · Kei Yagyu🇯🇵

    We present a complete set of decay rates of the Higgs boson with the mass of 125 GeV at the full next-to-leading order in a variety of extended Higgs models; i.e., a model with an additional real singlet scalar field, four types of two Higgs doublet models and the inert doublet model. All the one-loop contributions due to QCD and electroweak interactions as well as scalar interactions are taken into account, and the calculations are systematically performed. Branching ratios for all the decay modes are evaluated in these models, and patterns of deviations in each decay mode from the standard model predictions are comprehensively analyzed. We show how these models with extended Higgs sectors can be distinguished by using our calculation of the branching ratios and future precision measurements of the Higgs boson decays.

    hep-phNPB(2019)·38 citations
21. 21*

    Probing Proton Structure at the Large Hadron electron Collider

    Rabah Abdul Khalek🇳🇱 · Shaun Bailey🇬🇧 · Jun Gao🇨🇳 · Lucian Harland-Lang🇬🇧 · Juan Rojo🇳🇱

    For the foreseeable future, the exploration of the high-energy frontier will be the domain of the Large Hadron Collider (LHC). Of particular significance will be its high-luminosity upgrade (HL-LHC), which will operate until the mid-2030s. In this endeavour, for the full exploitation of the HL-LHC physics potential an improved understanding of the parton distribution functions (PDFs) of the proton is critical. The HL-LHC program would be uniquely complemented by the proposed Large Hadron electron Collider (LHeC), a high-energy lepton-proton and lepton-nucleus collider based at CERN. In this work, we build on our recent PDF projections for the HL-LHC to assess the constraining power of the LHeC measurements of inclusive and heavy quark structure functions. We find that the impact of the LHeC would be significant, reducing PDF uncertainties by up to an order of magnitude in comparison to state-of-the-art global fits. In comparison to the HL-LHC projections, the PDF constraints from the LHeC are in general more significant for small and intermediate values of the momentum fraction x. At higher values of x, the impact of the LHeC and HL-LHC data is expected to be of a comparable size, with the HL-LHC constraints being more competitive in some cases, and the LHeC ones in others. Our results illustrate the encouraging complementarity of the HL-LHC and the LHeC in terms of charting the quark and gluon structure of the proton.

    hep-phhep-exSciPost Phys.(2019)·33 citations
22. 22*

    Binary JUNIPR: an interpretable probabilistic model for discrimination

    Anders Andreassen🇺🇸 · Ilya Feige🇬🇧 · Christopher Frye🇬🇧 · Matthew D. Schwartz🇺🇸

    JUNIPR is an approach to unsupervised learning in particle physics that scaffolds a probabilistic model for jets around their representation as binary trees. Separate JUNIPR models can be learned for different event or jet types, then compared and explored for physical insight. The relative probabilities can also be used for discrimination. In this paper, we show how the training of the separate models can be refined in the context of classification to optimize discrimination power. We refer to this refined approach as Binary JUNIPR. Binary JUNIPR achieves state-of-the-art performance for quark/gluon discrimination and top-tagging. The trained models can then be analyzed to provide physical insight into how the classification is achieved. As examples, we explore differences between quark and gluon jets and between gluon jets generated with two different simulations.

    hep-phPRL(2019)·27 citations
23. 23*

    Dark matter interactions with muons in neutron stars

    Raghuveer Garani🇧🇪 · Julian Heeck🇺🇸

    Neutron stars contain a significant number of stable muons due to the large chemical potential and degenerate electrons. This makes them the unique vessel to capture muonphilic dark matter, which does not interact with other astrophysical objects, including Earth and its direct-detection experiments. The infalling dark matter can heat up the neutron star both kinetically and via annihilations, which is potentially observable with future infrared telescopes. New physics models for muonphilic dark matter can easily be motivated by, and connected to, existing anomalies in the muon sector, e.g., the anomalous magnetic moment or LHCb's recent hints for lepton-flavor non-universality in $B\to K{\mu }^{+}{\mu }^{-}$ decays. We study the implications for a model with dark matter charged under a local $U(1{)}_{L_{\mu }-L_{\tau }}$.

    hep-phastro-ph.COastro-ph.HEhep-exPRD(2019)·97 citations
24. 24*

    TMD parton shower effects in associated $\gamma$ + jet production at LHC

    A.V. Lipatov🇷🇺 · M.A. Malyshev🇷🇺 · H. Jung🇩🇪

    We investigate associated prompt photon and hadronic jet production at the LHC energies using the $k_T$-factorization approach. Our consideration is based on the $\mathcal{O}(\alpha {\alpha }_s^2)$ off-shell gluon-gluon fusion subprocess $g^{\ast }{g}^{\ast }\to \gamma q\bar{q}$ and several subleading quark-initiated contributions from $\mathcal{O}(\alpha {\alpha }_s)$ and $\mathcal{O}(\alpha {\alpha }_s^2)$ subprocesses, taken into account in the conventional (collinear) QCD factorization. The transverse momentum dependent (or unintegrated) gluon densities in a proton are derived from Catani-Ciafaloni-Fiorani-Marchesini (CCFM) evolution equation. We achieve reasonably good agreement with the experimental data taken by CMS and ATLAS Collaborations and demonstrate the importance of initial state parton showers for jet determination in the $k_T$-factorization approach.

    hep-phPRD(2019)·12 citations
25. 25*

    The Fate of Dense Scalar Stars

    Francesco Muia🇮🇹 · Michele Cicoli🇮🇹 · Katy Clough🇬🇧 · Francisco Pedro🇮🇹 · Fernando Quevedo🇬🇧 · Gian Paolo Vacca🇮🇹

    Long-lived pseudo-solitonic objects, known as oscillons/oscillatons, which we collectively call real scalar stars, are ubiquitous in early Universe cosmology of scalar field theories. Typical examples are axions stars and moduli stars. Using numerical simulations in full general relativity to include the effects of gravity, we study the fate of real scalar stars and find that depending on the scalar potential they are either meta-stable or collapse to black holes. In particular we find that for KKLT potentials the configurations are meta-stable despite the asymmetry of the potential, consistently with the results from lattice simulations that do not include gravitational effects. For $\alpha$-attractor potentials collapse to black holes is possible in a region of the parameter space where scalar stars would instead seem to be meta-stable or even disperse without including gravity. Each case gives rise to different cosmological implications which may affect the stochastic spectrum of gravitational waves.

    ↳ gr-qchep-phhep-thJCAP(2019)·41 citations
26. 26*

    Jumping Spectra and Vanishing Couplings in Heterotic Line Bundle Standard Models

    James Gray🇺🇸 · Juntao Wang🇺🇸

    We study two aspects of the physics of heterotic Line Bundle Standard Models on smooth Calabi-Yau threefolds. First, we investigate to what degree modern moduli stabilization scenarios can affect the standard model spectrum in such compactifications. Specifically, we look at the case where some of the complex structure moduli are fixed by a choice of hidden sector bundle. In this context, we study the frequency with which the system tends to be forced to a point in moduli space where the cohomology groups determining the spectrum in the standard model sector jump in dimension. Second, we investigate to what degree couplings, that are permitted by all of the obvious symmetries of the theory, actually vanish due to certain topological constraints associated to their higher dimensional origins. We find that both effects are prevalent within the data set of heterotic Line Bundle Standard Models studied.

    ↳ hep-thhep-phJHEP(2019)·17 citations
27. 27*

    String Phenomenology From a Worldsheet Perspective

    Alon E. Faraggi🇬🇧

    I argue that the ten dimensional non--supersymmetric tachyonic superstrings may serve as good starting points for the construction of viable phenomenological vacua. Thus, enlarging the space of possible solutions that may address some of the outstanding problems in string phenomenology. A tachyon free six generation Standard--like Model is presented, which can be regarded as an orbifold of the $SO(16)\times E_8$ heterotic--string in ten dimensions. I propose that any $(2,0)$ heterotic--string in four dimensions can be connected to a $(2,2)$ one via an orbifold or by interpolations and provide some evidence for this conjecture. It suggests that any Effective Field Theory (EFT) model that cannot be connected to a $(2,2)$ theory is necessarily in the swampland, and will simplify the analysis of the moduli spaces of $(2,0)$ string compactifications.

    ↳ hep-thhep-phEPJC(2019)·32 citations
28. 28*

    Nuclear modification of jet shape for inclusive jets and $\gamma$-jets at the LHC energies

    Ning-Bo Chang🇨🇳 · Yasuki Tachibana🇺🇸 · Guang-You Qin🇨🇳

    With our coupled jet-fluid model, we study the nuclear modifications of full jets and jet structures for single inclusive jets and $\gamma$-jets in Pb+Pb collisions at $5.02$~ATeV and $2.76$~ATeV. The in-medium evolution of full jet shower is described by a set of coupled transport equations including the effects of collisional energy loss, transverse momentum broadening and medium-induced splitting process. The dynamical evolution of bulk medium is simulated by solving relativistic hydrodynamic equation with source term which accounts for the energy and momentum deposited by hard jet shower to soft medium. Our study demonstrates that the hydrodynamic medium response to jet propagation significantly enhances the broadening of jet shape at large angles and is essential for the cone-size dependence of jet energy loss and nuclear modification factor of inclusive jet production. It is also found that the nuclear modification pattern of jet shape is sensitive to jet energy but has weak dependence on the flavor of the parton that initiates the jet. Our result can naturally explain the different nuclear modification patterns of jet shape functions for single inclusive jet and $\gamma$-jet events as observed by the CMS Collaboration, and can be tested in the future by measuring the jet shape function over a wider range of jet energies in heavy-ion collisions.

    ↳ nucl-thhep-phnucl-exPLB(2020)·60 citations
29. 29*

    Dark Sector Physics at the Belle II Experiment

    Gianluca Inguglia🇦🇹

    The Belle II experiment at the SuperKEKB energy-asymmetric $e^{+}{e}^{-}$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times 10^{35}$ cm${}^{-2}$s${}^{-1}$ and the Belle II experiment aims to record 50 ab${}^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run, achieved a peak luminosity of $5.5\times 10^{33}$ cm${}^{-2}$s${}^{-1}$, and Belle II has recorded a data sample of about 0.5 fb${}^{-1}$. Main operation of SuperKEKB has started in March 2019. Already this early data set with specifically designed triggers offers the possibility to search for a large variety of dark sector particles in the GeV mass range complementary to the Large Hadron Collider (LHC) and dedicated low energy experiments; these searches will benefit from more data in the process of being accumulated. This talk will review the state of the dark sector searches at Belle II with a focus on the discovery potential of the early data, and show the first results.

    ↳ hep-exhep-phNuovo Cim.C(2020)·3 citations
30. 30*

    Spectral Noncommutative Geometry, Standard Model and all that

    Agostino Devastato🇮🇹 · Maxim Kurkov🇮🇹 · Fedele Lizzi🇮🇹

    We review the approach to the standard model of particle interactions based on spectral noncommutative geometry. The paper is (nearly) self-contained and presents both the mathematical and phenomenological aspects. In particular the bosonic spectral action and the fermionic action are discussed in detail, and how they lead to phenomenology. We also discuss the Euclidean vs. Lorentz issues and how to go beyond the standard model in this framework.

    ↳ hep-thhep-phmath-phmath.MPInt.J.Mod.Phys.A(2019)·18 citations
31. 31*

    Highlights from the 7 year High Energy Starting Event sample in Icecube

    Kareem Farrag🇬🇧

    Here we outline the main highlights from the 7 year High Energy Starting Events (HESE) event sample. The next new physics search using astrophysical neutrino flavor data is described, where we reach the Planck scale for the first time.

    ↳ hep-exastro-ph.HEhep-ph0 citations
32. 32*

    Warm Quintessential Inflation

    Konstantinos Dimopoulos🇬🇧 · Leonora Donaldson-Wood🇬🇧

    We introduce warm quintessential inflation and study it in the weak dissipative regime. We consider the original quintessential inflation model, which approximates quartic chaotic inflation at early times and thawing quartic inverse-power-law quintessence at present. We find that the model successfully accounts for both inflation and dark energy observations, while it naturally reheats the Universe, thereby overcoming a major problem of quintessential inflation model-building.

    ↳ gr-qcastro-ph.COhep-phhep-thPLB(2019)·62 citations
33. 33*

    Evaluation of Entanglement Entropy in High Energy Elastic Scattering

    Robi Peschanski🇫🇷 · Shigenori Seki🇯🇵

    Entanglement of the two scattered particles is expected to occur in elastic collisions, even at high energy where they are in competition with inelastic ones. We study how to evaluate quantitatively the corresponding entanglement entropy $S_{\mathrm{EE}}.$ For this sake, we regularize the divergences occurring in the formal derivation of $S_{\mathrm{EE}}$ using a regularization procedure acting on the two-particle Hilbert space of final states. A quantitative application is performed in proton-proton collisions at collider energies, comparing the results of $S_{\mathrm{EE}}$ with two different cut-offs and with a volume-regularization obtained by a prescription fixing the finite two-body Hilbert space volume. A significant entanglement is found which persists even at the highest available energies.

    ↳ hep-thhep-phPRD(2019)·52 citations
34. 34*

    Neutrino currents in wakes of cosmic strings

    Sovan Sau🇮🇳 · Soma Sanyal🇮🇳

    Neutrinos rotating around Abelian Higgs strings will generate a neutral current close to the string. As the string moves through the cosmic plasma, the velocity kick generated by the motion of the string will enhance the neutrino current in the wake region. The neutrino current density depends on its distance from the string and is oscillatory in nature. This leads to neutrino density gradients in the plasma. Such a flux of neutrinos with periodic density fluctuations will lead to electron currents in the plasma. The current will act like a cross-perturbation across the cosmic string wake. The perturbation as well as the high Reynolds number of the plasma will result in the generation of magnetic fields in the wake of the cosmic string.

    ↳ astro-ph.COhep-phEPJC(2020)·9 citations
35. 35*

    Finite size of hardons and HBT interferometry for hydrodynamic sources

    Yong Zhang🇨🇳 · Hong-Jie Yin🇨🇳 · Weihua Wu🇨🇳

    Hadrons formed in heavy-ion collisions are not point-like objects, they cannot occupy too close space-time points. When the two bosons are too close to each other, their constituents start to mix and they cannot be considered as bosons subjected to Bose-Einstein statistics, this effect is called excluded volume effect. We study the volume effect on HBT for the sources with various sizes. The effect on HBT was shown in out, side and long directions, and it is more obvious for the source with a narrow space-time distribution. The correlation functions for high transverse momenta are more suppressed by the volume effect. Hence the incoherence parameter may be more suppressed by the volume effect for high transverse momenta in small collision systems.

    ↳ nucl-thhep-phIJMPE(2020)·0 citations
36. 36*

    Primordial black holes as a dark matter candidate are severely constrained by the Galactic Center 511 keV gamma-ray line

    Ranjan Laha🇨🇭

    We derive the strongest constraint on the fraction of dark matter that can be composed of low mass primordial black holes by using the observation of the Galactic Center 511 keV gamma-ray line. Primordial black holes of masses $\lesssim$ 10${}^{15}$ kg will evaporate to produce $e^{\pm }$ pairs. The positrons will lose energy in the Galactic Center, become non-relativistic, and then annihilate with the ambient electrons. We derive robust and conservative bounds by assuming that the rate of positron injection via primordial black hole evaporation is less than what is required to explain the SPI/ INTEGRAL observation of the Galactic Center 511 keV gamma-ray line. Depending on the primordial black hole mass function and other astrophysical uncertainties, these constraints are the most stringent in the literature and show that primordial black holes contribute to less than 1\% of the dark matter density. Our technique also probes part of the mass range which was completely unconstrained by previous studies.

    ↳ astro-ph.HEastro-ph.COgr-qchep-ph+1PRL(2019)·329 citations
37. 37*

    X-ray and gamma-ray limits on the primordial black hole abundance from Hawking radiation

    Guillermo Ballesteros🇪🇸 · Javier Coronado-Blázquez🇪🇸 · Daniele Gaggero🇪🇸

    The non-observation of Hawking radiation from primordial black holes of $10^{16}$g sets a conservative strong bound on their cosmological abundance. We revisit this bound and show how it can be improved (both in mass reach and strength) by an adequate modeling of the combined AGN and blazar emission in the MeV range. We also estimate the sensitivity to the primordial black hole abundance of a future X-ray experiment capable of identifying a significantly larger number of astrophysical sources contributing to the diffuse background in this energy range.

    ↳ astro-ph.COastro-ph.HEhep-phPLB(2020)·89 citations
38. 38*

    X-ray photon scattering at a focused high-intensity laser pulse

    Felix Karbstein🇩🇪 · Elena A. Mosman🇷🇺

    We study x-ray photon scattering in the head-on collision of an XFEL pulse and a focused high-intensity laser pulse, described as paraxial Laguerre-Gaussian beam of arbitrary mode composition. For adequately chosen relative orientations of the polarization vectors of the colliding laser fields, this gives rise to a vacuum birefringence effect manifesting itself in polarization flipped signal photons. Throughout this article the XFEL is assumed to be mildly focused to a waist larger than that of the high-intensity laser beam. As previously demonstrated for the special case of a fundamental paraxial Gaussian beam, this scenario is generically accompanied by a scattering phenomenon of x-ray energy signal photons outside the forward cone of the XFEL beam, potentially assisting the detection of the effect in experiment. Here, we study the fate of the x-ray scattering signal under exemplary deformations of the transverse focus profile of the high-intensity pump.

    ↳ physics.opticshep-phPRD(2019)·26 citations
39. 39*

    CMB-HD: An Ultra-Deep, High-Resolution Millimeter-Wave Survey Over Half the Sky

    Neelima Sehgal🇺🇸 · Simone Aiola🇺🇸 · Yashar Akrami🇫🇷 · Kaustuv Basu🇩🇪 · Michael Boylan-Kolchin🇺🇸 · Sean Bryan🇺🇸 · Sebastien Clesse🇧🇪 · Francis-Yan Cyr-Racine🇺🇸 · Luca Di Mascolo🇩🇪 · Simon Dicker🇺🇸 · Thomas Essinger-Hileman🇺🇸 · Simone Ferraro🇺🇸 and 28 other authors

    A millimeter-wave survey over half the sky, that spans frequencies in the range of 30 to 350 GHz, and that is both an order of magnitude deeper and of higher-resolution than currently funded surveys would yield an enormous gain in understanding of both fundamental physics and astrophysics. By providing such a deep, high-resolution millimeter-wave survey (about 0.5 uK-arcmin noise and 15 arcsecond resolution at 150 GHz), CMB-HD will enable major advances. It will allow 1) the use of gravitational lensing of the primordial microwave background to map the distribution of matter on small scales (k~10/hMpc), which probes dark matter particle properties. It will also allow 2) measurements of the thermal and kinetic Sunyaev-Zel'dovich effects on small scales to map the gas density and gas pressure profiles of halos over a wide field, which probes galaxy evolution and cluster astrophysics. In addition, CMB-HD would allow us to cross critical thresholds in fundamental physics: 3) ruling out or detecting any new, light (< 0.1eV), thermal particles, which could potentially be the dark matter, and 4) testing a wide class of multi-field models that could explain an epoch of inflation in the early Universe. Such a survey would also 5) monitor the transient sky by mapping the full observing region every few days, which opens a new window on gamma-ray bursts, novae, fast radio bursts, and variable active galactic nuclei. Moreover, CMB-HD would 6) provide a census of planets, dwarf planets, and asteroids in the outer Solar System, and 7) enable the detection of exo-Oort clouds around other solar systems, shedding light on planet formation. CMB-HD will deliver this survey in 5 years of observing half the sky, using two new 30-meter-class off-axis cross-Dragone telescopes to be located at Cerro Toco in the Atacama Desert. The telescopes will field about 2.4 million detectors (600,000 pixels) in total.

    ↳ astro-ph.COastro-ph.GAhep-phBull.Am.Astron.Soc.(2019)·177 citations
40. 40*

    Possible Hints of Sterile Neutrinos in Recent Measurements of the Hubble Parameter

    Graciela B. Gelmini🇺🇸 · Alexander Kusenko🇺🇸 · Volodymyr Takhistov🇺🇸

    Local Universe observations find a value of the Hubble constant $H_0$ that is larger than the value inferred from the Cosmic Microwave Background and other early Universe measurements, assuming known physics and the $\Lambda$CDM cosmological model. We show that additional radiation in active neutrinos produced just before Big Bang Nucleosynthesis by an unstable sterile neutrino with mass $m_s=$ O(10) MeV can alleviate this discrepancy. The necessary masses and couplings of the sterile neutrino, assuming it mixes primarily with ${\nu }_{\tau }$ and/or ${\nu }_{\mu }$ neutrinos, are within reach of Super-Kamiokande as well as upcoming laboratory experiments such as NA62 and DUNE.

    ↳ astro-ph.COhep-phJCAP(2021)·67 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.