Fri·Feb 17, 2017Friday·February 17, 2017

1. 01*

   Nonmaximal ${\theta }_{23}$ mixing at NOvA from neutrino decoherence

   Joao A. B. Coelho🇫🇷 · W. Anthony Mann🇺🇸 · Saqib S. Bashar🇺🇸

   In study of muon neutrino disappearance at 810 km, the NOvA experiment finds flavor mixing of the atmospheric sector to deviate from maximal (${\sin }^2{\theta }_{23}=0.5$) by 2.6 $\sigma$. The result is in tension with the 295-km baseline measurements of T2K which are consistent with maximal mixing. We propose that ${\theta }_{23}$ is in fact maximal, and that the disagreement is harbinger of environmentally-induced decoherence. The departure from maximal mixing can be accounted for by an energy-independent decoherence of strength $\Gamma =(2.3\pm 1.1)\times 10^{-23}$ GeV.

   hep-phhep-exPRL(2017)·48 citations
2. 02*

   Radiative Two-Loop Neutrino Masses with Dark Matter

   C. Simoes🇧🇪 · D. Wegman🇧🇪

   Using the Weinberg operator, we present a full collection of genuine two-loop models for neutrino mass generation, which contain a dark matter particle as one of the internal messengers. These models can be constructed simply by adding new fields that are singlets or doublets of SU(2)L. We ensure the stability of the dark matter candidate by the addition of a Z2 symmetry that will also be used to forbid tree level or one-loop diagrams. Thus we only present models where the main contribution for neutrinos masses is generated from the corresponding two-loop diagram. We also discuss a short outline corresponding to some phenomenological characteristics of these models.

   hep-phJHEP(2017)·19 citations
3. 03*

   Off-shell gluon production in interaction of a projectile with 2 or 3 targets

   M.A. Braun🇷🇺 · M.Yu. Salykin (Saint-Petersburg State University, Russia)🇷🇺

   Within the effective QCD action for the Regge kinematics amplitudes for virtual gluon emission are studied in collision of a projectile with two and three targets. It is demonstrated that all un- Feynman singularities cancel between induced vertices and rescattering contributions. Formulas simplify considerably in a special gauge which is a straightforward generalization of the light-cone gauge for emission of real gluons.

   hep-phEPJC(2017)·14 citations
4. 04*

   Backgrounds for Fast Simulation ${\mathbf{e}}^{+}{\mathbf{e}}^{-}$ Collider Studies at $\sqrt{\mathbf{s}}=91,250,350,500$ GeV

   C.T. Potter🇺🇸

   Various proposals for a new $e^{+}{e}^{-}$ collider operating below 1 TeV are now under consideration by the worlwide High Energy Physics community. Among these are the International Linear Collider and the Circular Electron Positron Collider. We describe high statistics Standard Model background simulation samples generated with MG5_aMC@NLO for $e^{+}{e}^{-}$ collider studies at $\sqrt{s}=91,250,350,500$ GeV. Fast detector simulation is performed with Delphes and DSiD, the detector card for the SiD detector. The samples are compared with other simulation samples generated with Whizard.

   hep-ph3 citations
5. 05*

   Effect of Quark Dimension Reduction on Goldstone Mode in Magnetic Field

   Shijun Mao🇨🇳 · Yuxuan Wang🇨🇳

   The meson static properties are investigated in Pauli-Villars regularized Nambu--Jona-Lasinio model in strong magnetic field. The quark dimension reduction leads to not only the magnetic catalysis effect on chiral symmetry restoration but also a sudden jump of the mass of the Goldstone mode at the Mott transition temperature.

   hep-phhep-thnucl-thPRD(2017)·48 citations
6. 06*

   Regularization with Numerical Extrapolation for Finite and UV-Divergent Multi-loop Integrals

   E.de Doncker🇺🇸 · F.Yuasa🇯🇵 · K.Kato🇯🇵 · T.Ishikawa🇯🇵 · J.Kapenga🇺🇸 · O.Olagbemi🇺🇸

   We give numerical integration results for Feynman loop diagrams such as those covered by Laporta [1] and by Baikov and Chetyrkin [2], and which may give rise to loop integrals with UV singularities. We explore automatic adaptive integration using multivariate techniques from the PARINT package for multivariate integration, as well as iterated in- tegration with programs from the QUADPACK package, and a trapezoidal method based on a double exponential trans- formation. PARINT is layered over MPI (Message Passing Interface), and incorporates advanced parallel/distributed techniques including load balancing among processes that may be distributed over a cluster or a network/grid of nodes. Results are included for 2-loop vertex and box diagrams and for sets of 2-, 3- and 4-loop self-energy diagrams with or without UV terms. Numerical regularization of integrals with singular terms is achieved by linear and non-linear extrapolation methods.

   hep-phComput.Phys.Commun.(2018)·22 citations
7. 07*

   Simply split SIMPs

   Nicolás Bernal🇨🇴 · Xiaoyong Chu🇦🇹 · Josef Pradler🇦🇹

   Dark Matter which interacts strongly with itself, but only feebly with the Standard Model is a possibility that has been entertained to solve apparent small-scale structure problems that are pertinent to the non-interacting cold Dark Matter paradigm. In this paper, we study the simple case in which the self-scattering rate today is regulated by kinematics and/or the abundance ratio, through the mass-splitting of nearly degenerate pseudo-Dirac fermions ${\chi }_1$ and ${\chi }_2$ or real scalars ${\varphi }_1$ and ${\varphi }_2$. We calculate the relic density of these states in a scenario where self-scattering proceeds through off-diagonal couplings with a vector particle $V$ (Dark Photon) and where the abundance is set through number-depleting 4-to-2 reactions in the hidden sector, or, alternatively, via freeze-in. We study the implications of the considered models and their prospect of solving astrophysical small-scale structure problems. We also show how the introduction of the (meta-)stable heavier state may be probed in future dark matter searches.

   hep-phPRD(2017)·92 citations
8. 08*

   Extended chiral Khuri-Treiman formalism for $\eta \to 3\pi$ and the role of the $a_0(980)$, $f_0(980)$ resonances

   M. Albaladejo🇪🇸 · B. Moussallam🇫🇷

   Recent experiments on $\eta \to 3\pi$ decays have provided an extremely precise knowledge of the amplitudes across the Dalitz region which represent stringent constraints on theoretical descriptions. We reconsider an approach in which the low-energy chiral expansion is assumed to be optimally convergent in an unphysical region surrounding the Adler zero, and the amplitude in the physical region is uniquely deduced by an analyticity-based extrapolation using the Khuri-Treiman dispersive formalism. We present an extension of the usual formalism which implements the leading inelastic effects from the $K\bar{K}$ channel in the final-state $\pi \pi$ interaction as well as in the initial-state $\eta \pi$ interaction. The constructed amplitude has an enlarged region of validity and accounts in a realistic way for the influence of the two light scalar resonances $f_0(980)$ and $a_0(980)$ in the dispersive integrals. It is shown that the effect of these resonances in the low energy region of the $\eta \to 3\pi$ decay is not negligible, in particular for the $3{\pi }^0$ mode, and improves the description of the energy variation across the Dalitz plot. Some remarks are made on the scale dependence and the value of the double quark mass ratio $Q$.

   hep-phEPJC(2017)·70 citations
9. 09*

   Charged Higgs bosons in the extended supersymmetric scenario at the LHC

   Priyotosh Bandyopadhyay🇮🇹

   We investigate an extension of the Minimal Supersymmetric Standard Model (MSSM) containing a $SU(2)$ Higgs triplet of zero hypercharge and a gauge singlet. We focus on a scenario of this model which allows a light pseudoscalar and/or a scalar below $100$ GeV in the spectrum, consistent with the most recent data from the LHC and the earlier data from the LEP experiments. The triplet extension gives rise to two additional charged Higgs bosons which do not couple to fermions but can decay into $Z{W}^{\pm }$. The presence of a very light pseudoscalar opens $a_1{W}^{\pm }$ decay mode for the light charged Higgs boson just like $Z_3$ symmetric singlet-extension (NMSSM). A triplet type charged Higgs can be produced via vector boson fusion at the tree-level which is absent in 2HDM and MSSM and NMSSM. If such charged Higgs boson is pair produced both $Z{W}^{\pm }$ and $a_1{W}^{\pm }$ decay modes can be probed which can prove the existence of triplet and singlet both.

   hep-phPoS(2016)·0 citations
10. 10*

    Anomalous dimension of the gauge invariant canonical decomposition for proton momentum with the background field method

    Yoshio Kitadono🇨🇳 · Pengming Zhang🇨🇳

    The anomalous dimension for the gauge-invariant-canonical decomposition of the energy-momentum tensor for quarks and gluons is studied by the background field method. In particular, the consistency between the background field method and the renormalization in the gluonic sectors is investigated. The analysis shows that the naive gauge-invariant-decomposition has an inconsistency between its definition and the renormalization in the background field method. Although we try to consider a trick to overcome this inconsistency in computing the anomalous dimension, the gauge-parameter dependence remains in the final result. This result should be extended to the problems on the gauge-invariant-canonical-spin decomposition.

    hep-ph1 citation
11. 11*

    Topological dark matter from the theory of composite electroweak symmetry breaking

    Yong-Liang Ma

    The lightest electroweak baryon as a topological object is investigated by using a general effective Lagrangian of composite electroweak symmetry breaking and the spin-independent electroweak baryon-nucleon scattering cross section is calculated. We explicitly show the masses of the electroweak baryons and the cross section as functions of the Peskin-Takeuchi $S$ parameter and the ratio of the masses of axial-vector and vector composite bosons. We find that it is acceptable to regard the electroweak baryon as a dark matter candidate and the even number of technicolor is favored.

    hep-phhep-exCommun.Theor.Phys.(2018)·4 citations
12. 12*

    Can invisible objects be `seen' via forward proton detectors at the LHC?

    V.A. Khoze🇬🇧 · A.D. Martin🇬🇧 · M.G. Ryskin🇬🇧

    We discuss the possibility of identifying invisible objects (e.g. dark matter) via missing mass in Central Exclusive Processes; that is, in events where only forward protons are detected at the LHC. We show that the signal must have a cross section greater than 0.25 fb in order that it can be detected. We estimate the huge background caused by soft proton dissociation and evaluate the requirements of the detector `veto' system needed to sufficiently suppress these events. In addition, we discuss the related process leading to the possible identification of the particles from the so-called `compressed-mass Beyond the Standard Model (BSM)' scenarios. In this case the background is not so severe.

    hep-phJ.Phys.G(2017)·15 citations
13. 13*

    Searching for New physics in Charm Radiative decays

    Aritra Biswas🇮🇳 · Sanjoy Mandal🇮🇳 · Nita Sinha🇮🇳

    We show that for a heavy vector-like quark model with a down type isosinglet, branching ratio for $c\to u\gamma$ decay is enhanced by more than $\mathcal{O}(10^2)$ as compared to that in the Standard model when QCD corrections to next-to-leading order are incorporated. In a left-right symmetric model (LRSM) along with a heavy vector-like fermion, enhancement of this order can be achieved at the bare (QCD uncorrected) level itself. We propose that a measurement of the photon polarization could be used to signal the presence of such new physics inspite of the large long distance effects. We find that there is a large region within the allowed parameter space of model with vector-like quark with additional left-right symmetry, where depending on the exact size of the long distance contribution, the photon polarization can be dominantly right-handed.

    hep-phhep-exInt.J.Mod.Phys.A(2018)·10 citations
14. 14*

    Impact of Recent RHIC Data on Helicity-Dependent Parton Distribution Functions

    Emanuele R. Nocera🇬🇧

    I study the impact of recent measurements performed at the Relativistic Heavy Ion Collider on the determination of helicity-dependent parton distribution functions of the proton. Specifically, I consider: preliminary data on longitudinally single-spin asymmetries for $W$-boson production recorded by the STAR experiment during the 2013 run at a center-of-mass energy $\sqrt{s}=510$ GeV; data on longitudinally double-spin asymmetries for di-jet production recorded by the STAR experiment during the 2009 run at $\sqrt{s}=200$ GeV; and data on longitudinally double-spin asymmetries for neutral pion production recorded by the PHENIX experiment during a series of runs between 2006 and 2013 at $\sqrt{s}=200$ GeV and $\sqrt{s}=510$ GeV. The impact of the new data is studied by applying Bayesian reweighting to NNPDFpol1.1, the most recent global analysis of helicity-dependent parton distribution functions based on the NNDPF methodology. In comparsion to NNDPFpol1.1, a slightly more positive polarized gluon PDF, extended to somewhat smaller values of momentum fractions with narrower uncertainties, as well as a slightly more marked and more precise asymmetry between polarized up and down sea quarks are found in this study.

    hep-ph11 citations
15. 15*

    Heavy quark production at the LHC in the Parton Reggeization Approach

    Anton Karpishkov🇷🇺 · Maxim Nefedov🇷🇺 · Vladimir Saleev🇷🇺 · Alexandra Shipilova🇷🇺

    We present the general introduction to the Parton Reggeization Approach and discuss some new results on large-p_T production for heavy quarks at the LHC. We concentrate here on study of different correlation spectra for b\barb-jet pairs, D\barD-meson pairs and DD-meson pairs.

    hep-ph1 citation
16. 16*

    Weak Boson Fusion at 100 TeV

    Dorival Goncalves🇺🇸 · Tilman Plehn🇩🇪 · Jennifer M. Thompson🇩🇪

    From the LHC runs we know that, with increasing collider energy, weak-boson-fusion Higgs production dominates as an environment for precision measurements. We show how a future hadron collider performs for three challenging benchmark signatures. Because all of these measurements rely on the tagging jet signature, we first give a comprehensive analysis of weak-boson-fusion kinematics and a proposed two-step jet veto at a 100 TeV hadron collider. We then find this machine to be sensitive to invisible Higgs branching ratios of 0.5%, a second-generation muon Yukawa coupling of 2%, and an enhanced total Higgs width of around 5%, the latter with essentially no model dependence. This kind of performance crucially relies on a sufficient detector coverage and a dedicated weak-boson-fusion trigger channel.

    hep-phPRD(2017)·27 citations
17. 17*

    Magnetic moments of octet baryons with deformed Uq(su(3)) flavor symmetry

    Niels G. Gresnigt🇨🇳 · Adam B. Gillard

    The effect of a q-deformation of flavor symmetry on octet baryon magnetic moments is investigated by taking the quantum group Uq(su(3)) as a flavor symmetry and calculating expressions for the magnetic moments of the octet baryons. Using the experimental values for the magnetic moments of the proton, neutron, and Lambda baryons as input, the magnetic moments of the up, down, and strange quarks, and by extension those of the remaining octet baryons, depend on the value of the deformation parameter q. Plotting the least square error as a function of q we find the undeformed value q=1 is a local maximum. Nearby are a relative minimum (at q=0.610) and an absolute minimum (at q=1.774). The value q=1.774 gives an approximately 10% decrease in the least square error compared to the undeformed case. For this value of q the quark masses of the up and down quarks are calculated to be 331 MeV and 305 MeV respectively.

    hep-phhep-th0 citations
18. 18*

    Chiral vortical effect with finite rotation, temperature, and curvature

    Antonino Flachi🇯🇵 · Kenji Fukushima🇯🇵

    We perform an explicit calculation of the axial current at finite rotation and temperature in curved space. We find that finite curvature and mass corrections to the chiral vortical effect satisfy a relation of the chiral gap effect, that is, a fermion mass-shift by a scalar curvature. We also point out that a product term of the angular velocity and the scalar curvature shares the same coefficient as the mixed gravitational chiral anomaly. We discuss possible applications of the curvature induced chiral vortical effect to rotating astrophysical compact objects described by the Kerr metric. Instead of direct calculation we assume that the Chern-Simons current can approximate the physical axial current. We make a proposal that the chiral vortical current from rotating compact objects could provide a novel microscopic mechanism behind the generation of collimated jets.

    ↳ hep-thhep-phPRD(2018)·59 citations
19. 19*

    Muon-neutrino-induced charged current pion production on nuclei

    U. Mosel · K. Gallmeister

    [Background] Long-Baseline experiments such as T2K, NOvA or the planned Deep Underground Neutrino Experiment (DUNE) require theoretical descriptions of the complete event in a neutrino-nucleus reaction. Since nuclear targets are used this requires a good understanding of neutrino-nucleus interactions. [Purpose] One of the dominant reaction channels in neutrino-nucleus interactions is pion production. This paper aims for a coherent view on all charged current charged pion production data that are avaible from the experiments MiniBooNE, the near detector experiment at T2K and MINERvA. [Methods] Pion production is treated through excitations of nucleon resonances, including background terms, and deep inelastic scattering. The final state interactions of the produced pions are described within the Giessen-Boltzmann-Uehling-Uhlenbeck (GiBUU) implementation of quantum-kinetic transport theory. [Results] Results are given for MiniBooNE, the near detector experiment at T2K and for MINERvA. While the theoretical results for MiniBooNE differ from the data both in shape and magnitude, their agreement both with the T2K and the MINERvA data is good for all pion and lepton observables. Predictions for pion spectra are shown for MicroBooNE and NOvA. [Conclusions] Based on the GiBUU model of lepton-nucleus interactions a consistent, good theoretical description of CC charged pion production data from the T2K ND and the MINERvA experiments is possible, without any parameter tunes. The MiniBooNE data cannot be reproduced.

    ↳ nucl-thhep-exhep-phnucl-exPhys. Rev. C 96, 015503 (2017)
20. 20*

    Impact of the latest measurement of Hubble constant on constraining inflation models

    Xin Zhang🇨🇳

    We investigate how the constraint results of inflation models are affected by considering the latest local measurement of $H_0$ in the global fit. We use the observational data, including the Planck CMB full data, the BICEP2 and Keck Array CMB B-mode data, the BAO data, and the latest measurement of Hubble constant, to constrain the $\Lambda$CDM+$r$+$N_{\mathrm{eff}}$ model, and the obtained 1$\sigma$ and 2$\sigma$ contours of $(n_s,r)$ are compared to the theoretical predictions of selected inflationary models. We find that, in this fit, the scale invariance is only excluded at the 3.3$\sigma$ level, and $\Delta N_{\mathrm{eff}}>0$ is favored at the 1.6$\sigma$ level. The natural inflation model is now excluded at more than 2$\sigma$ level; the Starobinsky $R^2$ model becomes only favored at around 2$\sigma$ level; the most favored model becomes the spontaneously broken SUSY inflation model; and, the brane inflation model is also well consistent with the current data, in this case.

    ↳ astro-ph.COgr-qchep-phhep-thSCPMA(2017)·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.