Mon·Aug 27, 2018Monday·August 27, 2018

1. 01*

   Correlations among elastic and inelastic cross-sections and slope parameter

   A. P. Samokhin🇷🇺

   We discuss the unitarity motivated relations among the elastic cross-section, slope parameter and inelastic cross-section of the high energy \textit{pp} interaction. In particular, the MacDowell-Martin unitarity bound is written down in another form to make a relation between the elastic and inelastic quantities more transparent. On the basis of an unitarity motivated relation we argue that the growth with energy of the elastic to total cross-section ratio is a consequence of the increasing with energy of the \textit{inelastic interaction intensity}. The latter circumstance is an underlying reason for the acceleration of the slope parameter growth, for the slowing of the growth of the elastic to total cross-section ratio and for other interesting phenomena, which are observed in the TeV energy range. All of this confirms the old idea that the elastic scattering is a shadow of the particle production processes.

   hep-phhep-exPLB(2018)·3 citations
2. 02*

   Stationary and non-stationary solutions of the evolution equation for neutrino in matter

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

   We study solutions of the equation which describes the evolution of a neutrino propagating in dense homogeneous medium in the framework of the quantum field theory. In the two-flavor model the explicit form of Green function is obtained, and as a consequence the dispersion law for a neutrino in matter is derived. It is shown that there exist both the solutions describing the stationary states and the solutions describing the spin-flavor coherent states of the neutrino. The stationary states may be different from the mass eigenstates, and the wave function of a state with a definite flavor should be constructed as a linear combination of the wave functions of the stationary states with coefficients, which depend on the mixing angle in matter. In the ultra-relativistic limit the wave functions of the spin-flavor coherent states coincide with the solutions of the quasi-classical evolution equation. Quasi-classical approximation of the wave functions of spin-flavor coherent states is used to calculate the probabilities of transitions between neutrino states with definite flavor and helicity.

   hep-phhep-thnucl-thEPJ Web Conf.(2018)·1 citation
3. 03*

   Natural Stabilization of the Higgs Boson's Mass and Alignment

   Kenneth Lane🇺🇸 · William Shepherd🇩🇪

   Current data from the LHC indicate that the 125 GeV Higgs boson, $H$, is either the single Higgs of the Standard Model or, to a good approximation, an "aligned Higgs". We propose that $H$ is the pseudo-Goldstone dilaton of Gildener and Weinberg. Models based on their mechanism of scale symmetry breaking can naturally account for the Higgs boson's low mass and aligned couplings. We conjecture that they are the only way to achieve a "Higgslike dilaton" that is actually the Higgs boson. These models further imply the existence of additional Higgs bosons in the vicinity of 200 to about 550 GeV. We illustrate our proposal in a version of the two-Higgs-doublet model of Lee and Pilaftsis. Our version of this model is consistent with published precision electroweak and collider physics data. We describe tests to confirm, or exclude, this model at Run 3 of the LHC.

   hep-phhep-exPRD(2019)·27 citations
4. 04*

   Non-Universal Gaugino Masses in the NMSSM

   Junichiro Kawamura🇯🇵 · Tatsuo Kobayashi🇯🇵 · Natsumi Nagata🇯🇵

   The Next-to-Minimal Supersymmetric Standard Model (NMSSM) provides a natural framework to realize a low-scale supersymmetric (SUSY) model, where a singlet superfield is added to the minimal model to generate a SUSY-scale higgsino mass term with its vacuum expectation value. Due to the presence of the extra singlet field, the vacuum conditions to realize the correct electroweak symmetry-breaking become fairly restrictive especially if we impose universality conditions at the unification scale. In this paper, we show that a non-universal gaugino mass spectrum can significantly relax this restriction even though the scalar masses and trilinear couplings are subject to universality conditions. With the gaugino non-universality, we find that higgsino can be the lightest SUSY particle and its thermal relic abundance can reproduce the observed dark matter density in a wide range of parameter space in which the 125~GeV Higgs-boson mass is obtained. This higgsino-like dark matter may be probed in direct detection experiments. We also find that there is an upper bound on the masses of supersymmetric particles in this scenario, and many model points predict colored particles such as gluino to be within the reach of a future 100~TeV collider. Implications for no-scale/gaugino-mediation models are also discussed.

   hep-phJHEP(2018)·2 citations
5. 05*

   Eddy magnetization from the chiral Barnett effect

   Kenji Fukushima🇯🇵 · Shi Pu🇯🇵 · Zebin Qiu🇯🇵

   We discuss the spin, the angular momentum, and the magnetic moment of rotating chiral fermions using a kinetic theory. We find that, in addition to the chiral vortical contribution along the rotation axis, finite circular spin polarization is induced by the spin-momentum correlation of chiral fermions, which is canceled by a change in the orbital angular momentum. We point out that the eddy magnetic moment is nonvanishing due to the $g$-factors, exhibiting the chiral Barnett effect.

   hep-phcond-mat.quant-gasPRA(2019)·17 citations
6. 06*

   Structure of the ${\Xi }_b(6227{)}^{-}$ Resonance

   T. M. Aliev🇹🇷 · K. Azizi🇹🇷 · Y. Sarac🇹🇷 · H. Sundu🇹🇷

   We explore the recently observed ${\Xi }_b(6227{)}^{-}$ resonance to fix its quantum numbers. To this end, we consider various possible scenarios: It can be considered as either 1P/2S excitations of the ${\Xi }_b^{-}$ and ${\Xi }_b^{\prime }(5935{)}^{-}$ ground state baryons with spin-$\frac{1}{2}$ or 1P/2S excitations of the ground state ${\Xi }_b(5955{)}^{-}$ with spin-$\frac{3}{2}$. We calculate the masses of the possible angular-orbital $1P$ and $2S$ excited states corresponding to each channel employing the QCD sum rule technique. It is seen that all the obtained masses are in agreement with the experimentally observed value, implying that the mass calculations are not enough to distinguish the quantum numbers of the state under question. Therefore, we extend the analysis to investigate the possible decays of the same excited states into ${\Lambda }_b^0{K}^{-}$ and ${\Xi }_b^{-}\pi$. Using the light cone QCD sum rule method, we calculate the corresponding strong coupling constants, which are used to extract the decay widths of the modes under consideration. Our results on decay widths indicate that the ${\Xi }_b(6227{)}^{-}$ is $1P$ angular-orbital excited state of the ${\Xi }_b(5955{)}^{-}$ baryon with quantum numbers $J^P={\frac{3}{2}}^{-}$.

   hep-phhep-exhep-latPRD(2018)·38 citations
7. 07*

   Majoron Dark Matter and Constraints on the Majoron-Neutrino Coupling

   Tim Brune🇩🇪 · Heinrich Päs🇩🇪

   We revisit a singlet Majoron model in which neutrino masses arise from the spontaneous violation of lepton number. If the Majoron obtains a mass of order MeV, it can play the role of dark matter. We discuss constraints on the couplings of the massive Majoron with masses of order MeV to neutrinos from supernova data. In the dense supernova core, Majoron-emitting neutrino annihilations are allowed and can change the signal of a supernova. Based on the observation of SN1987A, we exclude a large range of couplings from the luminosity and the deleptonization arguments, taking the effect of the background medium into account. If the Majoron mass does not exceed the Q-value of the experiment, the neutrino-Majoron couplings allow for neutrinoless double beta decay with Majoron emission. We derive constraints on the couplings for a Majoron mass of order MeV based on the phase space suppression and the diminishing signal-to-background ratio due to the Majoron mass. The combination of constraints from astrophysics and laboratory experiments excludes a large range of neutrino-Majoron couplings in the mass range of intererest for Majoron dark matter.

   hep-phPRD(2019)·116 citations
8. 08*

   Closing the window on single leptoquark solutions to the $B$-physics anomalies

   Andrei Angelescu🇺🇸 · Damir Bečirević🇫🇷 · Darius A. Faroughy🇸🇮 · Olcyr Sumensari🇮🇹

   We examine various scenarios in which the Standard Model is extended by a light leptoquark state to solve for one or both $B$-physics anomalies, viz. $R_{D^{(\ast )}}^{\exp }>R_{D^{(\ast )}}^{\mathrm{SM}}$ or/and $R_{K^{(\ast )}}^{\exp }<R_{K^{(\ast )}}^{\mathrm{SM}}$. To do so we combine the constraints arising both from the low-energy observables and from direct searches at the LHC. We find that none of the scalar leptoquarks of mass $m_{\mathrm{LQ}}\simeq 1$ TeV can alone accommodate the above mentioned anomalies. The only single leptoquark scenario which can provide a viable solution for $m_{\mathrm{LQ}}\simeq 1÷2$ TeV is a vector leptoquark, known as $U_1$, which we re-examine in its minimal form (letting only left-handed couplings to have non-zero values). We find that the limits deduced from direct searches are complementary to the low-energy physics constraints. In particular, we find a rather stable lower bound on the lepton flavor violating $b\to s{\ell }_1^{\pm }{\ell }_2^{\mp }$ modes, such as $\mathcal{B}(B\to K\mu \tau )$. Improving the experimental upper bound on $\mathcal{B}(B\to K\mu \tau )$ by two orders of magnitude could compromise the viability of the minimal $U_1$ model as well.

   hep-phJHEP(2018)·315 citations
9. 09*

   Alternative Perspective on Gauged Lepton Number and Implications for Collider Physics

   We-Fu Chang🇹🇼 · John N. Ng🇨🇦

   A new anomaly-free gauged $U(1{)}_{\ell }$ lepton-number model is studied. Two standard model lepton generations acquire the same but oppositive sign $U(1{)}_{\ell }$ charges, while four exotic chiral leptons cancel the anomalies of the remaining lepton family. We discuss a simplified case which has the universal Yukawa couplings. It agrees with all the experimental constraints and predicts $m_e,m_{\mu }\ll m_{\tau }$, and the latter is of the electroweak scale. Due to the interference between the SM and $U(1{)}_{\ell }$ gauge interactions, this model robustly predicts that $e,\mu ,\tau$ have distinctive forward-backward asymmetries at the $e^{+}{e}^{-}$ colliders. It can be searched for at the $e^{+}{e}^{-}$ machine with $\sim$ TeV center-of-mass energy and an integrated luminosity $\sim a{b}^{-1}$.

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

    DUNE as the Next-Generation Solar Neutrino Experiment

    Francesco Capozzi🇩🇪 · Shirley Weishi Li🇺🇸 · Guanying Zhu🇺🇸 · John F. Beacom🇺🇸

    We show that the Deep Underground Neutrino Experiment (DUNE), with significant but feasible new efforts, has the potential to deliver world-leading results in solar neutrinos. With a 100 kton-year exposure, DUNE could detect $\gtrsim 10^5$ signal events above 5 MeV electron energy. Separate precision measurements of neutrino-mixing parameters and the ${}^8$B flux could be made using two detection channels (${\nu }_e+{}^{40}$Ar and ${\nu }_{e,\mu ,\tau }+e^{-}$) and the day-night effect ($>10\sigma$). New particle physics may be revealed through the comparison of solar neutrinos (with matter effects) and reactor neutrinos (without), which is discrepant by $\sim 2\sigma$ (and could become $5.6\sigma$). New astrophysics may be revealed through the most precise measurement of the ${}^8$B flux (to 2.5\%) and the first detection of the {\it hep} flux (to 11\%). {\it DUNE is required:} No other experiment, even proposed, has been shown capable of fully realizing these discovery opportunities.

    hep-phastro-ph.SRhep-exnucl-th+1PRL(2019)·164 citations
11. 11*

    Hadronic corrections to $\mu$-$e$ scattering at NNLO with space-like data

    Matteo Fael🇩🇪

    The Standard Model prediction for $\mu$-$e$ scattering at Next-to-Next-to-Leading Order (NNLO) contains non-perturbative QCD contributions given by diagrams with a hadronic vacuum polarization insertion in the photon propagator. By taking advantage of the hyperspherical integration method, we show that the subset of hadronic NNLO corrections where the vacuum polarization appears inside a loop, the irreducible diagrams, can be calculated employing the hadronic vacuum polarization in the space-like region, without making use of the $R$ ratio and time-like data. We present the analytic expressions of the kernels necessary to evaluate numerically the two types of irreducible diagrams: the two-loop vertex and box corrections. As a cross check, we evaluate these corrections numerically and we compare them with the results given by the traditional dispersive approach and with analytic two-loop vertex results in QED.

    hep-phhep-latJHEP(2019)·61 citations
12. 12*

    Casimir Effect in (2+1)-dimensional Yang-Mills Theory as a Probe of the Magnetic Mass

    Dimitra Karabali🇺🇸 · V.P. Nair🇺🇸

    We consider the Casimir effect in a gauge-invariant Hamiltonian formulation of nonabelian gauge theories in (2+1) dimensions, for an arbitrary gauge group. We show that the result is in good agreement with recent lattice simulations. We also argue that the Casimir effect may be viewed as a good probe of magnetic screening effects in (3+1)-dimensional gauge theories at high temperatures.

    ↳ hep-thhep-lathep-phPRD(2018)·28 citations
13. 13*

    Hair distributions in noncommutative Einstein-Born-Infeld black holes

    Yan Peng🇨🇳

    We study hair mass distributions in noncommutative Einstein-Born-Infeld hairy black holes with non-zero cosmological constants. We find that the larger noncommutative parameter makes the hair easier to condense in the near horizon area. We also show that Hod's lower bound can be evaded in the noncommutative gravity. However, for large black holes with a non-negative cosmological constant, Hod's lower hair mass bound almost holds in the sense that nearly half of the hair lays above the photonsphere.

    ↳ gr-qchep-phhep-thNPB(2019)·22 citations
14. 14*

    New constraints on inelastic dark matter from IceCube

    Riccardo Catena🇸🇪 · Fredrik Hellström🇸🇪

    We study the capture and subsequent annihilation of inelastic dark matter (DM) in the Sun, placing constraints on the DM-nucleon scattering cross section from the null result of the IceCube neutrino telescope. We then compare such constraints with exclusion limits on the same cross section that we derive from XENON1T, PICO and CRESST results. We calculate the cross section for inelastic DM-nucleon scattering within an extension of the effective theory of DM-nucleon interactions which applies to the case of inelastic DM models characterised by a mass splitting between the incoming and outgoing DM particle. We find that for values of the mass splitting parameter larger than about 200 keV, neutrino telescopes place limits on the DM-nucleon scattering cross section which are stronger than the ones from current DM direct detection experiments. The exact mass splitting value for which this occurs depends on whether DM thermalises in the Sun or not. This result applies to all DM-nucleon interactions that generate DM-nucleus scattering cross sections which are independent of the nuclear spin, including the "canonical" spin-independent interaction. We explicitly perform our calculations for a DM candidate with mass of 1 TeV, but our conclusions qualitatively also apply to different masses. Furthermore, we find that exclusion limits from IceCube on the coupling constants of this family of spin-independent interactions are more stringent than the ones from a (hypothetical) reanalysis of XENON1T data based on an extended signal region in nuclear recoil energy. Our results should be taken into account in global analyses of inelastic DM models.

    ↳ astro-ph.COhep-phJCAP(2018)·21 citations
15. 15*

    Despicable Dark Relics: generated by gravity with unconstrained masses

    Malcolm Fairbairn🇬🇧 · Kimmo Kainulainen🇫🇮 · Tommi Markkanen🇬🇧 · Sami Nurmi🇫🇮

    We demonstrate the existence of a generic, efficient and purely gravitational channel producing a significant abundance of dark relics during reheating after the end of inflation. The mechanism is present for any inert scalar with the non-minimal curvature coupling $\xi R{\chi }^2$ and the relic production is efficient for natural values $\xi =\mathcal{O}(1)$. The observed dark matter abundance can be reached for a broad range of relic masses extending from $m\sim 1\mathrm{keV}$ to $m\sim 10^8\mathrm{GeV}$, depending on the scale of inflation and the dark sector couplings. Frustratingly, such relics escape direct, indirect and collider searches since no non-gravitational couplings to visible matter are needed.

    ↳ astro-ph.COgr-qchep-phJCAP(2019)·85 citations
16. 16*

    To $B$ or not to $B$: Primordial magnetic fields from Weyl anomaly

    André Benevides🇮🇹 · Atish Dabholkar🇮🇹 · Takeshi Kobayashi🇮🇹

    The quantum effective action for the electromagnetic field in an expanding universe has an anomalous dependence on the scale factor of the metric arising from virtual charged particles in the loops. It has been argued that this Weyl anomaly of quantum electrodynamics sources cosmological magnetic fields in the early universe. We examine this long-standing claim by using the effective action beyond the weak gravitational field limit which has recently been determined. We introduce a general criteria for assessing the quantumness of field fluctuations, and show that the Weyl anomaly is not able to convert vacuum fluctuations of the gauge field into classical fluctuations. We conclude that there is no production of coherent magnetic fields in the universe from the Weyl anomaly of quantum electrodynamics, irrespective of the number of massless charged particles in the theory.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2018)·15 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.