Mon·May 29, 2017Monday·May 29, 2017

1. 01*

   Sensitivity limits on heavy-light mixing $|U_{\mu N}{|}^2$ from lepton number violating $B$ meson decays

   Gorazd Cvetic🇨🇱 · C.S. Kim🇰🇷

   We consider the lepton number violating decays $B\to {\mu }^{\pm }{\mu }^{\pm }{\pi }^{\mp }$ and $B\to D^{(\ast )}{\mu }^{\pm }{\mu }^{\pm }{\pi }^{\mp }$ which may be detected at LHCb and Belle-II experiments; and $B\to {\mu }^{\pm }{\mu }^{\pm }{e}^{\mp }\nu$ and $B\to D^{(\ast )}{\mu }^{\pm }{\mu }^{\pm }{e}^{\mp }\nu$ decays which may be detected at Belle-II experiment. The projected total number of produced $B$ mesons is $4.8\times 10^{12}$ at LHCb upgrade and $5\times 10^{10}$ at Belle-II. For the case that the above decays are not detected, we deduce the new upper bounds (sensitivity limits) for the mixing parameter $|U_{\mu N}{|}^2$ of heavy sterile neutrino with sub-eV light neutrino, as a function of the sterile neutrino mass in the interval $1.75\mathrm{GeV}<M_N<5.0\mathrm{GeV}$. We take into account the probability of decay of the sterile neutrino $N$ within the detector, taking as the effective detector length $L=2.3m$ at LCHb upgrade and $L=1m$ at Belle-II. In the interval $1.75\mathrm{GeV}<M_N<3\mathrm{GeV}$, the most stringent bounds can be obtained with the decays $B\to {\mu }^{\pm }{\mu }^{\pm }{\pi }^{\mp }$ at LHCb upgrade. The sensitivity limits are expected to be in general more stringent at LHCb upgrade than at Belle-II, principally because the number of produced $B$ mesons in LHCb upgrade is expected to be by about two orders of magnitude larger than at Belle-II. We conclude that the LHCb upgrade and Belle-II experiments have the potential to either find a new heavy Majorana neutrino $N$, or to improve significantly the sensitivity limits (upper bounds) on the heavy-light mixing parameter $|U_{\mu N}{|}^2$, particularly in the mass range $1.75\mathrm{GeV}<M_N<3\mathrm{GeV}$. This work is a continuation and refinement of our previous work [1] on the subject.

   hep-phPRD(2017)·34 citations
2. 02*

   Chiral magnetohydrodynamics for heavy-ion collisions

   Yuji Hirono🇺🇸

   The chiral magnetic effect (CME) is a macroscopic transport effect resulting from the chiral anomaly. We review the recent progress in theoretical understanding the properties of chiral plasmas, in which the CME and other anomaly-induced transports take place. In particular, the nontrivial interplay of anomalous currents and dynamical electromagnetic fields is discussed. We also review the theoretical status of the modeling of anomalous transport effects in heavy-ion collisions.

   hep-phnucl-thNPA(2017)·5 citations
3. 03*

   Lepton masses and mixing in a scotogenic model

   E. C. F. S. Fortes🇦🇷 · A. C. B. Machado🇧🇷 · J. Montaño🇧🇷 · V. Pleitez🇧🇷

   We consider an extension of the standard model with three Higgs doublet model and $S_3\times {\mathbb{Z}}_2$ discrete symmetries. Two of the scalar doublets are inert due to the ${\mathbb{Z}}_2$ symmetry. We have calculated all the mass spectra in the scalar and lepton sectors and accommodated the leptonic mixing matrix as well. We also show that the model has scalar and pseudoscalar candidates to dark matter. Constraints on the parameters of the model coming from the decay $\mu \to e\gamma$ were considered and we found signals between the current and the upcoming experimental limits, and from that decay we can predict the one-loop $\mu \to ee\bar{e}$ channel.

   hep-phPLB(2020)·8 citations
4. 04*

   Fuzzy Dark Matter and Non-Standard Neutrino Interactions

   Vedran Brdar🇩🇪 · Joachim Kopp🇩🇪 · Jia Liu🇩🇪 · Pascal Prass🇩🇪 · Xiao-Ping Wang (JGU Mainz)🇩🇪

   We discuss novel ways in which neutrino oscillation experiments can probe dark matter. In particular, we focus on interactions between neutrinos and ultra-light ("fuzzy") dark matter particles with masses of order $10^{-22}$ eV. It has been shown previously that such dark matter candidates are phenomenologically successful and might help ameliorate the tension between predicted and observed small scale structures in the Universe. We argue that coherent forward scattering of neutrinos on fuzzy dark matter particles can significantly alter neutrino oscillation probabilities. These effects could be observable in current and future experiments. We set new limits on fuzzy dark matter interacting with neutrinos using T2K and solar neutrino data, and we estimate the sensitivity of reactor neutrino experiments and of future long-baseline accelerator experiments. These results are based on detailed simulations in GLoBES. We allow the dark matter particle to be either a scalar or a vector boson. In the latter case, we find potentially interesting connections to models addressing various $B$ physics anomalies.

   hep-phastro-ph.HEhep-exPRD(2018)·113 citations
5. 05*

   Possibility of searching for $B_c^{\ast }$ $\to$ $B_{u,d,s}V$, $B_{u,d,s}P$ decays

   Junfeng Sun🇨🇳 · Yueling Yang🇨🇳 · Na Wang🇨🇳 · Qin Chang🇨🇳 · Gongru Lu🇨🇳

   The $B_c^{\ast }$ $\to$ $B_{u,d,s}V$, $B_{u,d,s}P$ decays are investigated with the QCD factorization approach, where $V$ and $P$ denote the ground $SU(3)$ vector and pseudoscalar mesons, respectively. The $B_c^{\ast }$ $\to$ $B_{u,d,s}$ transition form factors are calculated with the Wirbel-Stech-Bauer model. It is found that branching ratios for the color-favored and Cabibbo-favored $B_c^{\ast }$ $\to$ $B_s\rho$, $B_s\pi$ decays can reach up to $\mathcal{O}(10^{-7})$, which might be measurable in the future LHC experiments.

   hep-phhep-exPRD(2017)·6 citations
6. 06*

   Study of Non-Standard Charged-Current Interactions at the MOMENT experiment

   Jian Tang🇨🇳 · Yibing Zhang🇨🇳

   MuOn-decay MEdium baseline NeuTrino beam experiment (MOMENT) is a next-generation accelerator neutrino experiment looking for more physics study. We try to simulate neutrino oscillations confronting with Charged-Current\&Non-Standard neutrino Interactions(CC-NSIs) at MOMENT. These NSIs could alter neutrino production and detection processes and get involved in neutrino oscillation channels. We separate a perturbative discussion of oscillation channels at near and far detectors, and analyze parameter correlations with the impact of CC-NSIs. Taking ${\delta }_{cp}$ and ${\theta }_{23}$ as an example, we find that CC-NSIs can induce bias in precision measurements of standard oscillation parameters. In addition, a combination of near and far detectors using Gd-doped water cherenkov technology at MOMENT is able to provide good constraints of CC-NSIs happening at the neutrino production and detection processes.

   hep-phhep-exPRD(2018)·20 citations
7. 07*

   Comment on "On the implementation of CVC in weak charged-current proton-neutron transitions" by C. Giunti, arXiv: 1602.00215 [hep-ph]

   A. N. Ivanov🇦🇹

   We show that the term maintaining conservation of the charged vector current for the transitions "neutron <-> proton" even for different masses of the neutron and proton (see T. Leitner et al., Phys. Rev. C {\bf 73}, 065502 (2006) and A. M. Ankowski, arXiv:1601.06169 [hep-ph]) is related to the first class current contribution but not to the second class one as has been pointed out by C. Giunti, arXiv: 1602.00215 [hep-ph].

   hep-phastro-ph.COhep-exnucl-ex+15 citations
8. 08*

   Renormalization and radiative corrections to masses in a general Yukawa model

   M. Fox🇦🇹 · W. Grimus🇦🇹 · M. Löschner🇦🇹

   We consider a model with arbitrary numbers of Majorana fermion fields and real scalar fields ${\phi }_a$, general Yukawa couplings and a ${\mathbb{Z}}_4$ symmetry that forbids linear and trilinear terms in the scalar potential. Moreover, fermions become massive only after spontaneous symmetry breaking of the ${\mathbb{Z}}_4$ symmetry by vacuum expectation values (VEVs) of the ${\phi }_a$. Introducing the shifted fields $h_a$ whose VEVs vanish, $\overline{\text{mbox}MS}$ renormalization of the parameters of the unbroken theory suffices to make the theory finite. However, in this way, beyond tree level it is necessary to perform finite shifts of the tree-level VEVs, induced by the finite parts of the tadpole diagrams, in order to ensure vanishing one-point functions of the $h_a$. Moreover, adapting the renormalization scheme to a situation with many scalars and VEVs, we consider the physical fermion and scalar masses as derived quantities, $\text{i.e.}$ as functions of the coupling constants and VEVs. Consequently, the masses have to be computed order by order in a perturbative expansion. In this scheme we compute the selfenergies of fermions and bosons and show how to obtain the respective one-loop contributions to the tree-level masses. Furthermore, we discuss the modification of our results in the case of Dirac fermions and investigate, by way of an example, the effects of a flavour symmetry group.

   hep-phInt.J.Mod.Phys.A(2018)·13 citations
9. 09*

   MSSM-inspired multifield inflation

   M. N. Dubinin (1)🇷🇺 · E. Yu. Petrova (1 and 2)🇷🇺 · E. O. Pozdeeva (1)🇷🇺 · M. V. Sumin (2)🇷🇺 · S. Yu. Vernov (1) ((1) Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, (2) Physics Department, Lomonosov Moscow State University)🇷🇺

   Despite the fact that experimentally with a high degree of statistical significance only a single Standard Model--like Higgs boson is discovered at the LHC, extended Higgs sectors with multiple scalar fields not excluded by combined fits of the data are more preferable theoretically for internally consistent realistic models of particle physics. We analyze the inflationary scenarios which could be induced by the two-Higgs doublet potential of the Minimal Supersymmetric Standard Model (MSSM) where five scalar fields have nonminimal couplings to gravity. Observables following from such MSSM-inspired multifield inflation are calculated and a number of consistent inflationary scenarios are constructed. Cosmological evolution with different initial conditions for the multifield system leads to consequences fully compatible with observational data on the spectral index and the tensor-to-scalar ratio. It is demonstrated that the strong coupling approximation is precise enough to describe such inflationary scenarios.

   hep-phastro-ph.COgr-qchep-thJHEP(2017)·13 citations
10. 10*

    Selected strong decays of $\eta (2225)$ and $\varphi (2170)$ as $\Lambda \bar{\Lambda }$ bound states

    Yubing Dong🇨🇳 · Amand Faessler🇩🇪 · Thomas Gutsche🇩🇪 · Qifang Lü🇨🇳 · Valery E. Lyubovitskij🇩🇪

    The strong decays of the two resonances $\eta (2225)$ and $\varphi (2170)$ are discussed for selected decay channels. The two resonances are considered as the $\Lambda \bar{\Lambda }$ bound states in the molecular scenario. The phenomenological hadronic molecular approach is employed for the calculation of respective decay modes using effective Lagrangians. Our results show that the decay modes $\eta (2225)\to K^{\ast }K$ and $\varphi (2175)\to KK$ dominate over the partial decay widths of $\eta (2275)\to VV(\varphi \varphi ,\omega \omega ,K^{\ast }{K}^{\ast })$ and $\varphi (2175)\to VS(\omega \sigma ,K^{\ast }{K}_0^{\ast }(800),\varphi f_0(980))$ due to phase space and couplings.

    hep-phPRD(2017)·68 citations
11. 11*

    Relaxation of the Composite Higgs Little Hierarchy

    Brian Batell🇺🇸 · Michael A. Fedderke🇺🇸 · Lian-Tao Wang🇺🇸

    We describe a composite Higgs scenario in which a cosmological relaxation mechanism naturally gives rise to a hierarchy between the weak scale and the scale of spontaneous global symmetry breaking. This is achieved through the scanning of sources of explicit global symmetry breaking by a relaxion field during an exponentially long period of inflation in the early universe. We explore this mechanism in detail in a specific composite Higgs scenario with QCD-like dynamics, based on an ultraviolet $SU(N{)}_{\text{TC}}$ 'technicolor' confining gauge theory with three Dirac technifermion flavors. We find that we can successfully generate a hierarchy of scales $\xi \equiv ⟨h{⟩}^2/F_{\pi }^2\gtrsim 1.2\times 10^{-4}$ (i.e., compositeness scales $F_{\pi }\sim 20$ TeV) without tuning. This evades all current electroweak precision bounds on our (custodial violating) model. While directly observing the heavy composite states in this model will be challenging, a future electroweak precision measurement program can probe most of the natural parameter space for the model. We also highlight signatures of more general composite Higgs models in the cosmological relaxation framework, including some implications for flavor and dark matter.

    hep-phJHEP(2017)·33 citations
12. 12*

    Relativistic wide-angle galaxy bispectrum on the light-cone

    Daniele Bertacca🇩🇪 · Alvise Raccanelli🇺🇸 · Nicola Bartolo🇮🇹 · Michele Liguori🇮🇹 · Sabino Matarrese🇮🇹 · Licia Verde🇪🇸

    Given the important role that the galaxy bispectrum has recently acquired in cosmology and the scale and precision of forthcoming galaxy clustering observations, it is timely to derive the full expression of the large-scale bispectrum going beyond approximated treatments which neglect integrated terms or higher-order bias terms or use the Limber approximation. On cosmological scales, relativistic effects that arise from observing on the past light-cone alter the observed galaxy number counts, therefore leaving their imprints on N-point correlators at all orders. In this paper we compute for the first time the bispectrum including all general relativistic, local and integrated, effects at second order, the tracers' bias at second order, geometric effects as well as the primordial non-Gaussianity contribution. This is timely considering that future surveys will probe scales comparable to the horizon where approximations widely used currently may not hold; neglecting these effects may introduce biases in estimation of cosmological parameters as well as primordial non-Gaussianity.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2018)·53 citations
13. 13*

    Multiwavelength Analysis of Dark Matter Annihilation and RX-DMFIT

    Alex McDaniel🇺🇸 · Tesla Jeltema🇺🇸 · Stefano Profumo🇺🇸 · Emma Storm🇳🇱

    Dark matter (DM) particles are predicted by several well motivated models to yield Standard Model particles through self-annihilation that can potentially be detected by astrophysical observations. In particular, the production of charged particles from DM annihilation in astrophysical systems that contain magnetic fields yields radio emission through synchrotron radiation and X-ray emission through inverse Compton scattering of ambient photons. We introduce RX-DMFIT, a tool used for calculating the expected secondary emission from DM annihilation. RX-DMFIT includes a wide range of customizable astrophysical and particle parameters and incorporates important astrophysics including the diffusion of charged particles, relevant radiative energy losses, and magnetic field modelling. We demonstrate the use and versatility of RX-DMFIT by analyzing the potential radio and X-ray signals for a variety of DM particle models and astrophysical environments including galaxy clusters, dwarf spheroidal galaxies and normal galaxies. We then apply RX-DMFIT to a concrete example using Segue I radio data to place constraints for a range of assumed DM annihilation channels. For WIMP models with $M_{\chi }\le 100$ GeV and assuming weak diffusion, we find that the the leptonic ${\mu }^{+}{\mu }^{-}$ and ${\tau }^{+}{\tau }^{-}$ final states provide the strongest constraints, placing limits on the DM particle cross-section well below the thermal relic cross-section, while even for the $b\bar{b}$ channel we find limits close to the thermal relic cross-section. Our analysis shows that radio emission provides a highly competitive avenue for dark matter searches.

    ↳ astro-ph.HEastro-ph.COhep-phJCAP(2017)·52 citations
14. 14*

    SU(4) flavor symmetry breaking in D-meson couplings to light hadrons

    C.E. Fontoura🇧🇷 · J. Haidenbauer🇩🇪 · G. Krein🇧🇷

    The validity of SU(4)-flavor symmetry relations of couplings of charmed $D$ mesons to light mesons and baryons is examined with the use of ${}^3{\mathrm{P}}_0$ quark-pair creation model and nonrelativistic quark model wave functions. We focus on the three-meson couplings $\pi \pi \rho$, $KK\rho$ and $DD\rho$ and baryon-baryon-meson couplings $NN\pi$, $N\Lambda K$ and $N{\Lambda }_{c}D$. It is found that SU(4)-flavor symmetry is broken at the level of 30% in the $DD\rho$ tree-meson couplings and 20% in the baryon-baryon-meson couplings. Consequences of these findings for DN cross sections and existence of bound states D-mesons in nuclei are discussed.

    ↳ nucl-thhep-phEPJA(2017)·16 citations
15. 15*

    An analytic superfield formalism for tree superamplitudes in D=10 and D=11

    Igor Bandos🇪🇸

    Tree amplitudes of 10D supersymmetric Yang-Mills theory (SYM) and 11D supergravity (SUGRA) are collected in multi-particle counterparts of analytic on-shell superfields. These have essentially the same form as their chiral 4D counterparts describing $\mathcal{N}=4$ SYM and $\mathcal{N}=8$ SUGRA, but with components dependent on a different set of bosonic variables. These are the D=10 and D=11 spinor helicity variables, the set of which includes the spinor frame variable (Lorentz harmonics) and a scalar density, and generalized homogeneous coordinates of the coset $\frac{SO(D-2)}{SO(D-4)\otimes U(1)}$ (internal harmonics). We present an especially convenient parametrization of the spinor harmonics (Lorentz covariant gauge fixed with the use of an auxiliary gauge symmetry) and use this to find (a gauge fixed version of) the 3-point tree superamplitudes of 10D SYM and 11D SUGRA which generalize the 4 dimensional anti-MHV superamplitudes.

    ↳ hep-thgr-qchep-phJHEP(2018)·15 citations
16. 16*

    Lattice implementation of Abelian gauge theories with Chern-Simons number and an axion field

    Daniel G. Figueroa🇨🇭 · Mikhail Shaposhnikov🇨🇭

    Real time evolution of classical gauge fields is relevant for a number of applications in particle physics and cosmology, ranging from the early Universe to dynamics of quark-gluon plasma. We present a lattice formulation of the interaction between a $shift$-symmetric field and some $U(1)$ gauge sector, $a(x){\tilde{F}}_{\mu \nu }{F}^{\mu \nu }$, reproducing the continuum limit to order $\mathcal{O}(d{x}_{\mu }^2)$ and obeying the following properties: (i) the system is gauge invariant and (ii) shift symmetry is exact on the lattice. For this end we construct a definition of the {\it topological number density} $Q={\tilde{F}}_{\mu \nu }{F}^{\mu \nu }$ that admits a lattice total derivative representation $Q={\Delta }_{\mu }^{+}{K}^{\mu }$, reproducing to order $\mathcal{O}(d{x}_{\mu }^2)$ the continuum expression $Q={\partial }_{\mu }{K}^{\mu }\propto \vec{E}\cdot \vec{B}$. If we consider a homogeneous field $a(x)=a(t)$, the system can be mapped into an Abelian gauge theory with Hamiltonian containing a Chern-Simons term for the gauge fields. This allow us to study in an accompanying paper the real time dynamics of fermion number non-conservation (or chirality breaking) in Abelian gauge theories at finite temperature. When $a(x)=a(\vec{x},t)$ is inhomogeneous, the set of lattice equations of motion do not admit however a simple explicit local solution (while preserving an $\mathcal{O}(d{x}_{\mu }^2)$ accuracy). We discuss an iterative scheme allowing to overcome this difficulty.

    ↳ hep-latastro-ph.COhep-phNPB(2018)·42 citations
17. 17*

    Origin of the tentative AMS antihelium events

    Adam Coogan🇺🇸 · Stefano Profumo🇺🇸

    We demonstrate that the tentative detection of a few antihelium events with the Alpha Magnetic Spectrometer (AMS) on board the International Space Station can, in principle, be ascribed to the annihilation or decay of Galactic dark matter, when accounting for uncertainties in the coalescence process leading to the formation of antinuclei. We show that the predicted antiproton rate, assuming the antihelium events came from dark matter, is marginally consistent with AMS data, as is the antideuteron rate with current available constraints. We argue that a dark matter origin can be tested with better constraints on the coalescence process, better control of misidentified events, and with future antideuteron data.

    ↳ astro-ph.HEhep-phPRD(2017)·51 citations
18. 18*

    Anisotropic hydrodynamic modeling of 2.76 TeV Pb-Pb collisions

    Mubarak Alqahtani🇺🇸 · Mohammad Nopoush🇺🇸 · Radoslaw Ryblewski🇵🇱 · Michael Strickland🇺🇸

    We compare phenomenological results from 3+1d quasiparticle anisotropic hydrodynamics (aHydroQP) with experimental data collected in LHC 2.76 TeV Pb-Pb collisions. In particular, we present comparisons of particle spectra, average transverse momentum, elliptic flow, and HBT radii. The aHydroQP model relies on the introduction of a single temperature-dependent quasiparticle mass which is fit to lattice QCD data. By taking moments of the resulting Boltzmann equation, we obtain the dynamical equations used in the hydrodynamic stage which include the effects of both shear and bulk viscosities. At freeze-out, we use anisotropic Cooper-Frye freeze-out performed on a fixed-energy-density hypersurface to convert to hadrons. To model the production and decays of the hadrons we use THERMINATOR 2 which is customized to sample from ellipsoidal momentum-space distribution functions. Using smooth Glauber initial conditions, we find very good agreement with many heavy-ion collision observables.

    ↳ nucl-thhep-phPRC(2017)·83 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.