Tue·Mar 20, 2018Tuesday·March 20, 2018

1. 01*

   Exploring physics beyond the Standard Electroweak Model in the light of supersymmetry

   Pradipta Ghosh🇮🇳

   In this thesis we try to discuss certain phenomenological aspects of an R-parity violating non-minimal supersymmetric model, called $\mu \nu$SSM. We show that $\mu \nu$SSM can provide a solution to the $\mu$-problem of supersymmetry and can simultaneously accommodate the existing three flavour global data from neutrino experiments even at the tree level with the simple choice of flavour diagonal neutrino Yukawa couplings. We show that it is also possible to achieve different mass hierarchies for light neutrinos at the tree level itself. In $\mu \nu$SSM, the effect of R-parity violation together with a seesaw mechanism with TeV scale right-handed neutrinos are instrumental for light neutrino mass generation. We also analyze the stability of tree level neutrino masses and mixing with the inclusion of one-loop radiative corrections. In addition, we investigate the sensitivity of the one-loop corrections to different light neutrino mass orderings. Decays of the lightest supersymmetric particle were also computed and ratio of certain decay branching ratios was observed to correlate with certain neutrino mixing angle. We extend our analysis for different natures of the lightest supersymmetric particle as well as with various light neutrino mass hierarchies. We present estimation for the length of associated displaced vertices for various natures of the lightest supersymmetric particle which can act as a discriminating feature at a collider experiment. We also present an unconventional signal of Higgs boson in supersymmetry which can lead to a discovery, even at the initial stage of the large hadron collider running. Besides, we show that a signal of this kind can also act as a probe to the seesaw scale. Certain other phenomenological issues have also been addressed.

   hep-phhep-ex0 citations
2. 02*

   Insight on confinement using scalar field interactions

   R. Markazi🇲🇦 · N. El Biaze🇲🇦

   The scalar field plays an fundamental role in the investigation of confinement property characterising many particle physics models. This is achieved by coupling this particle directly with gauge fields at the lagrangian level. We have adopted the same approach {[}10{]} to determine a potential as a perturbative series in terms of interquark distance. In order to introduce the gravitational effects and inspired from bag models, we implement a scalar field which interacts both with the vacuum and the electron field. In this context and with presence of the vacuum condensates, it is possible to derive a more accurate expression of the electron energy.

   hep-ph0 citations
3. 03*

   Leading Pomeron Contributions and the TOTEM Data at 13 TeV

   M. Broilo🇧🇷 · E.G.S. Luna🇧🇷 · M.J. Menon🇧🇷

   The recent data by the TOTEM Collaboration on ${\sigma }_{tot}$ and $\rho$ at 13 TeV, have shown agreement with a leading Odderon contribution at the highest energies, as demonstrated in the very recent analysis by Martynov and Nicolescu (MN). In order to investigate the same dataset by means of Pomeron dominance, we introduce a general class of forward scattering amplitude, with leading contributions even under crossing, associated with simple, double and triple poles in the complex angular momentum plane. For the lower energy region, we consider the usual non-degenerated Regge trajectories, with even and odd symmetry. The analytic connection between ${\sigma }_{tot}$ and $\rho$ is obtained by means of dispersion relations and we carry out fits to $pp$ and $\bar{p}p$ data in the interval $\sqrt{s}=5$ GeV - 13 TeV; following MN we consider only the TOTEM data at the LHC energy region. From the fits, we conclude that the general analytic model, as well as some particular cases representing standard parameterizations, are not able to describe satisfactorily the ${\sigma }_{tot}$ and $\rho$ data at 13 TeV. Further analyses in course and some perspectives are outlined.

   hep-phhep-ex7 citations
4. 04*

   Subleading-power corrections to the radiative leptonic $B\to \gamma \ell \nu$ decay in QCD

   Yu-Ming Wang🇨🇳 · Yue-Long Shen🇨🇳

   Applying the method of light-cone sum rules with photon distribution amplitudes, we compute the subleading-power correction to the radiative leptonic $B\to \gamma \ell \nu$ decay, at next-to-leading order in QCD for the twist-two contribution and at leading order in ${\alpha }_s$ for the higher-twist contributions, induced by the hadronic component of the collinear photon. The leading-twist hadronic photon effect turns out to preserve the symmetry relation between the two $B\to \gamma$ form factors due to the helicity conservation, however, the higher-twist hadronic photon corrections can yield symmetry-breaking effect already at tree level in QCD. Using the conformal expansion of photon distribution amplitudes with the non-perturbative parameters estimated from QCD sum rules, the twist-two hadronic photon contribution can give rise to approximately 30\% correction to the leading-power "direct photon" effect computed from the perturbative QCD factorization approach. In contrast, the subleading-power corrections from the higher-twist two-particle and three-particle photon distribution amplitudes are estimated to be of $\mathcal{O}(3\sim 5\%)$ with the light-cone sum rule approach. We further predict the partial branching fractions of $B\to \gamma \ell \nu$ with a photon-energy cut $E_{\gamma }\ge E_{\mathrm{cut}}$, which are of interest for determining the inverse moment of the leading-twist $B$-meson distribution amplitude thanks to the forthcoming high-luminosity Belle II experiment at KEK.

   hep-phhep-exhep-latJHEP(2018)·84 citations
5. 05*

   A novel Dual Chiral Density Wave in nuclear matter based on a parity doublet structure

   Yusuke Takeda🇯🇵 · Hiroaki Abuki🇯🇵 · Masayasu Harada🇯🇵

   We study the Dual Chiral Density Wave (DCDW) in nuclear matter using a hadronic model with the parity doublet structure. We first extend the ordinary DCDW ansatz so as to incorporate the effect of an explicit chiral symmetry breaking. Then via numerically evaluating and minimizing the effective potential, we determine the phase structure. We find, in addition to the ordinary DCDW phase where the space average of the chiral condensate vanishes, a new DCDW phase (sDCDW) with a nonvanishing space average depending on the value of the chiral invariant mass parameter.

   hep-phnucl-thPRD(2018)·17 citations
6. 06*

   Multiple jets and $\gamma$-jet correlation in high-energy heavy-ion collisions

   Tan Luo (CCNU)🇨🇳 · Shanshan Cao (Wayne State Univ)🇺🇸 · Yayun He (CCNU and LBNL)🇨🇳 · Xin-Nian Wang (CCNU and LBNL)🇨🇳

   $\gamma$-jet production is considered one of the best probes of the hot quark-gluon plasma in high-energy heavy-ion collisions since the direct $\gamma$ can be used to gauge the initial energy and momentum of the associated jet. This is investigated within the Linear Boltzmann Transport (LBT) model for jet propagation and jet-induced medium excitation. With both parton energy loss and medium response from jet-medium interaction included, LBT can describe experimental data well on $\gamma$-jet correlation in Pb+Pb collisions at the Large Hadron Collider. Multiple jets associated with direct $\gamma$ production are found to contribute significantly to $\gamma$-jet correlation at small $p_T^{\mathrm{jet}}<p_T^{\gamma }$ and large azimuthal angle relative to the opposite direction of $\gamma$. Jet medium interaction not only suppresses the leading jet at large $p_T^{\mathrm{jet}}$ but also sub-leading jets at large azimuthal angle. This effectively leads to the narrowing of $\gamma$-jet correlation in azimuthal angle instead of broadening due to jet-medium interaction. The $\gamma$-jet profile on the other hand will be broadened due to jet-medium interaction and jet-induced medium response. Energy flow measurements relative to the direct photon is illustrated to reflect well the broadening and jet-induced medium response.

   hep-phPLB(2018)·118 citations
7. 07*

   $Z^{\prime }$ portal dark matter in the minimal $B-L$ model

   Satomi Okada🇯🇵

   In this review article, we consider a dark matter scenario in the context of the minimal extension of the Standard Model (SM) with a $B-L$ (baryon number minus lepton number) gauge symmetry, where three right-handed neutrinos with a $B-L$ charge $-1$ and a $B-L$ Higgs field with a $B-L$ charge $+2$ are introduced to make the model anomaly-free and to break the $B-L$ gauge symmetry, respectively. The $B-L$ gauge symmetry breaking generates the Majorana masses for the right-handed neutrinos. We introduce a Z${}_2$ symmetry to the model and assign an odd parity only for one right-handed neutrino, and hence the Z${}_2$-odd right-handed neutrino is stable and the unique dark matter candidate in the model. The so-called minimal seesaw works with the other two right-handed neutrinos and reproduces the current neutrino oscillation data. We consider the case that the dark matter particle communicates with the SM particles through the $B-L$ gauge boson ($Z_{B-L}^{\prime }$ boson), and obtain a lower bound on the $B-L$ gauge coupling (${\alpha }_{B-L}$) as a function of the $Z_{B-L}^{\prime }$ boson mass ($m_{Z^{\prime }}$) from the observed dark matter relic density. On the other hand, we interpret the recent LHC Run-2 results on the search for a $Z^{\prime }$ boson resonance to an upper bound on ${\alpha }_{B-L}$ as a function of $m_{Z^{\prime }}$. These two constraints are complementary to narrow down an allowed parameter region for this "$Z^{\prime }$ portal" dark matter scenario, leading to a lower mass bound of $m_{Z^{\prime }}\ge 3.9$ TeV.

   hep-phastro-ph.COhep-exAdv.High Energy Phys.(2018)·79 citations
8. 08*

   The Strong Decays of $P-$wave Mixing Heavy-Light $1^{+}$ States

   Yi Zhang🇨🇳 · Zhi-Hui Wang · Tian-hong Wang · Yue Jiang🇨🇳 · Qiang Li🇨🇳 · Guo-Li Wang

   Many $P-$wave mixing heavy-light $1^{+}$ states have not been discovered by experiment, some of them have been discovered but without the information of width, or with large uncertainty widths. In this paper, we study the strong decays of $P-$wave mixing heavy-light $1^{+}$ states $D^0$, $D^{\pm }$, $D_s^{\pm }$, $B^0$, $B^{\pm }$ and $B_s$ by the improved Bethe-Salpeter(B-S) method in two conditions of mixing angle $\theta$: one is $\theta =35.3^{\circ }$; another is considering the correction to mixing angle $\theta =35.3^{\circ }+{\theta }_1$. And we get some valuable predictions of the strong decay widths: $\Gamma (D_1^{\prime 0})=232$ MeV, $\Gamma (D_1^0)=21.5$ MeV, $\Gamma (D_1^{\prime \pm })=232$ MeV, $\Gamma (D_1^{\pm })=21.5$ MeV, $\Gamma (D_{s1}^{\prime \pm })=0.0101$ MeV, $\Gamma (D_{s1}^{\pm })=0.950$ MeV, $\Gamma (B_1^{\prime \pm })=263$ MeV, $\Gamma (B_1^{\pm })=16.8$ MeV, $\Gamma (B_{s1}^{\prime })=0.01987$ MeV and $\Gamma (B_{s1})=0.412$ MeV. We find that the decay widths of $D_{s1}^{\pm }$ and $B_{s1}$ are very sensitive to the mixing angle. And our results will provide the theoretical assistance by the future experiments.

   hep-phCPC(2018)·16 citations
9. 09*

   Electromagnetic multipole moments of the $P_c^{+}(4380)$ pentaquark in light-cone QCD

   U. Ozdem🇹🇷 · K. Azizi🇹🇷

   We calculate the electromagnetic multipole moments of the $P_c^{+}(4380)$ pentaquark by modeling it as the diquark-diquark-antiquark and ${\bar{D}}^{\ast }{\Sigma }_c$ molecular state with quantum numbers $J^P={\frac{3}{2}}^{-}$. In particular, the magnetic dipole, electric quadrupole and magnetic octupole moments of this particle are extracted in the framework of light-cone QCD sum rule. The values of the electromagnetic multipole moments obtained via two pictures differ substantially from each other, which can be used to pin down the underlying structure of $P_c^{+}(4380)$. The comparison of any future experimental data on the electromagnetic multipole moments of the $P_c^{+}(4380)$ pentaquark with the results of the present work can shed light on the nature and inner quark organization of this state.

   hep-phhep-exhep-latEPJC(2018)·38 citations
10. 10*

    Tetraquarks in the 1/N Expansion: a New Appraisal

    Luciano Maiani🇮🇹 · Antonio D. Polosa🇮🇹 · Veronica Riquer🇮🇹

    We discuss the necessary, albeit not sufficient, conditions for tetraquark poles to occur in the 1/N expansion of QCD and find the minimum order at which such poles may appear. Assuming tetraquark poles, we find a new non-planar solution with the minimal number of topologies and tetraquark species. The solution implies narrow states. Mixing with quarkonium states is allowed so that P-wave tetraquarks with J^PC=1^-- would couple to e^+e^-.

    hep-phPRD(2018)·20 citations
11. 11*

    Analysis of Angular Observables of ${\Lambda }_b\to \Lambda (\to p\pi ){\mu }^{+}{\mu }^{-}$ Decay in Standard and $Z^{\prime }$ Models

    Aqsa Nasrullah🇵🇰 · M. Jamil Aslam🇵🇰 · Saba Shafaq🇵🇰

    In 2015, the LHCb collaboration has measured $\frac{d\mathcal{B}}{d{q}^2}$, the lepton- and hadron-side forward-backward asymmetries, denoted by $A_{FB}^{\ell }$ and $A_{FB}^{\Lambda }$, respectively in the range $15<q^2(=s)<20$ GeV${}^2$ with 3 fb${}^{-1}$ of data. Motivated by these measurements, we perform an analysis of $q^2$ dependent ${\Lambda }_b\to \Lambda (\to p\pi ){\mu }^{+}{\mu }^{-}$ angular observables at large- and low-recoil in the SM and in a family non-universal $Z^{\prime }$ model. In the present study we use the recently performed high-precision lattice QCD calculations of the form factors that have well controlled uncertainties especially in $15<s<20$ GeV${}^2$ bin. Using the full four-folded angular distribution of ${\Lambda }_b\to \Lambda (\to p\pi ){\mu }^{+}{\mu }^{-}$ decay, firstly we calculate the values of these measured quantitites in the SM and compare their numerical values with the measurements in appropriate bins of $s$. In case of the possible discrepancy between the SM prediction and measurements, we try to see if these can be accommodated though the extra neutral $Z^{\prime }$ boson. In addition, the fraction of longitudinal polarization of the dimuon $F_L$ is measured to be $0.61_{-0.14}^{+0.11}\pm 0.03$ in $15<s<20$ GeV${}^2$ at the LHCb. We find that in this bin the value found in the $Z^{\prime }$ model is close to the observed values. After comparing the results of these observables, we have proposed a number of other observables whose values are calculated in different bins of $s$ in the SM and $Z^{\prime }$ model. We illustrate that the experimental observations of these observables in several bins of $s$ can help to test the predictions of the SM and unravel NP contributions arises due to $Z^{\prime }$ model in these decays.

    hep-phPTEP(2018)·7 citations
12. 12*

    Comments on the SU(4) dark matter

    Edward Shuryak🇺🇸

    We discuss possible scale of $SU(4)$ dark matter, in form of neutral baryons. We argue that it is very likely that those would have time to cluster into large "nuclear drops" in which they are Bose-condensed.

    hep-ph1 citation
13. 13*

    Leading Logarithms of the Two Point Function in Massless O(N) and SU(N) Models to any Order from Analyticity and Unitarity

    B. Ananthanarayan🇮🇳 · Shayan Ghosh🇮🇳 · Alexey Vladimirov🇩🇪 · Daniel Wyler🇨🇭

    Leading (large) logarithms in non-renormalizable theories have been investigated in the recent past. Besides some general considerations, explicit results for the expansion coefficients (in terms of leading logarithms) of partial wave amplitudes and of scalar and vector form factors have been given. Analyticity and unitarity constraints haven been used to obtain the expansion coefficients of partial waves in massless theories, yielding form factors and the scalar two-point function to five-loop order in the O(4)/O(3) model. Later, the all order solutions for the partial waves in any O(N+1)/O(N) model were found. Also, results up to four-loop order exist for massive theories. Here we extend the implications of analyticity and unitarity constraints on the leading logarithms to arbitrary loop order in massless theories. We explicitly obtain the scalar and vector form factors as well as to the scalar two-point function in any O(N) and SU(N) type models. We present relations between the expansion coefficients of these quantities and those of of the relevant partial waves. Our work offers a consistency check on the published results in the O(N) models for form factors, and new results for the scalar two-point function. For the SU(N) type models, we use the known expansion coefficients for partial waves to obtain those for scalar and vector form factors as well as for the scalar two-point function. Our results for the form factor offer a check for the known and future results for massive O(N) and SU(N) type models when the massless limit is taken. Mathematica notebooks which can be used to calculate the expansion coefficients are provided as ancillary files.

    hep-phEPJA(2018)·6 citations
14. 14*

    Analysis of the baryonic state $|[qc]c⟩$

    Sergey Koshkarev🇪🇪 · Stefan Groote🇪🇪

    In this note we analyse the structure of the baryonic state $|[qc]c⟩$ with a spin-0 diquark $[qc]$, as compared to baryonic states $|(qc)c⟩$ and $|q(cc)⟩$ containing internal spin-1 diquark states. While one can identify the state $|q(cc)⟩$ with the state observed at LHCb, the state $|(qc)c⟩$ could probably be part of the state ${\Xi }_{cc}^{++}(3780)$. Accordingly, the ground state of $|[qc]c⟩$ can be identified with the state ${\Xi }_{cc}^{+}(3520)$.

    hep-ph2 citations
15. 15*

    Non-global logarithms in jet and isolation cone cross sections

    Marcel Balsiger🇨🇭 · Thomas Becher🇨🇭 · Ding Yu Shao🇨🇭

    Starting from a factorization theorem in effective field theory, we derive a parton-shower equation for the resummation of non-global logarithms. We have implemented this shower and interfaced it with a tree-level event generator to obtain an automated framework to resum the leading logarithm of non-global observables in the large-$N_c$ limit. Using this setup, we compute gap fractions for dijet processes and isolation cone cross sections relevant for photon production. We compare our results with fixed-order computations and LHC measurements. We find that naive exponentiation is often not adequate, especially when the vetoed region is small, since non-global contributions are enhanced due to their dependence on the veto-region size. Since our parton shower is derived from first principles and based on renormalization-group evolution, it is clear what ingredients will have to be included to perform resummations at subleading logarithmic accuracy in the future.

    hep-phJHEP(2018)·51 citations
16. 16*

    New Physics in the Rayleigh-Jeans Tail of the CMB

    Maxim Pospelov🇨🇦 · Josef Pradler🇦🇹 · Joshua T. Ruderman🇺🇸 · Alfredo Urbano🇨🇭

    We show that despite stringent constraints on the shape of the main part of the CMB spectrum, there is considerable room for its modification within its Rayleigh-Jeans (RJ) end, $\omega \ll T_{\mathrm{CMB}}$. We construct explicit New Physics models that give an order one (or larger) increase of photon count in the RJ tail, which can be tested by existing and upcoming experiments aiming to detect the cosmological 21 cm emission/absorption signal. This class of models stipulates the decay of unstable particles to dark photons, $A^{\prime }$, that have a small mass, $m_{A^{\prime }}\sim 10^{-14}-10^{-9}$ eV, non-vanishing mixing angle $ϵ$ with electromagnetism, and energies much smaller than $T_{\mathrm{CMB}}$. The non-thermal number density of dark photons can be many orders of magnitude above the number density of CMB photons, and even a small probability of $A^{\prime }\to A$ oscillations, for values of as small as $ϵ\sim 10^{-9}$, can significantly increase the number of RJ photons. In particular, we show that resonant oscillations of dark photons into regular photons in the interval of redshifts $20<z<1700$ can be invoked as an explanation of the recent tentative observation of a stronger-than-expected absorption signal of 21 cm photons. We present a model that realizes this possibility, where milli-eV mass dark matter decays to dark photons, with a lifetime longer than the age of the Universe.

    hep-phastro-ph.COPRL(2018)·170 citations
17. 17*

    A numerical formulation of resummation in effective field theory

    Christian W. Bauer🇺🇸 · Pier Francesco Monni🇨🇭

    In this article we show how the resummation of infrared and collinear logarithms within Soft-Collinear Effective Theory (SCET) can be formulated in a way that makes it suitable for a Monte-Carlo implementation. This is done by applying the techniques developed for automated resummation using the branching formalism, which have resulted in the general resummation approach CAESAR/ARES. This work builds a connection between the two resummation approaches, and paves the way to automated resummation in SCET. As a case study we consider the resummation of the thrust distribution in electron-positron collisions at next-to-leading logarithm (NLL). However, the results presented here are easily generalizable to more complicated observables and processes as well as to higher orders in the logarithmic accuracy.

    hep-phJHEP(2019)·10 citations
18. 18*

    Cosmological Aspects of the Clockwork Axion

    Andrew J. Long🇺🇸

    The clockwork axion refers to a family of aligned multi-axion models that lead to an exponential hierarchy between the scale of Peccei-Quinn symmetry breaking and the scale of the axion decay constant. The clockworking can bring the Peccei-Quinn-scale particles to within reach of collider experiments.In this work we are interested in whether cosmological observations impose any new constraints on the clockwork axion. If the universe reheats above the scale of Peccei-Quinn breaking, then the ensuing cosmological phase transition produces a network of topological defects, which have a qualitatively different behavior from the string-wall network in the usual axion models. We estimate the relic abundances of axion dark matter and dark radiation that arise from the emission of axions by the defect network, and we infer a constraint on the scale of Peccei-Quinn breaking and the mass spectrum. We find that the defect contribution to the axion dark matter relic abundance is generally negligible. However, the defect production of relativistic axion dark radiation becomes significant if the scale of Peccei-Quinn symmetry breaking is larger than $100\mathrm{TeV}$, and measurements of $\Delta N_{\mathrm{eff}}$ provide a new probe of this class of models.

    hep-phastro-ph.COJHEP(2018)·42 citations
19. 19*

    Effective Field Theory description of Phantom Fields

    Elcio Abdalla🇧🇷

    In this work I show that a simple Field Theory on a non trivial gauge background may behave as a phantom field and contribute to an effective $w<-1$ state equation fluid contribution to cosmology.

    hep-phgr-qchep-th1 citation
20. 20*

    Exclusive vector meson production at an electron-ion collider

    Michael Lomnitz🇺🇸 · Spencer Klein🇺🇸

    Coherent exclusive vector meson electroproduction is a key physics channel at an electron-ion collider. It probes the gluon structure of nuclei over a wide range of $Q^2$, and can be used to measure nuclear shadowing and to search for gluon saturation and/or the colored glass condensate. In this paper, we present calculations of the kinematic distributions for a variety of exclusive vector meson final states: the $\rho$, $\varphi$, J/$\psi$, ${\psi }^{\prime }$ and the ${\rm Y}$ states. The cross-sections for light and $c\overline{c}$ mesons are large, while ${\rm Y}$ states should be produced in moderate numbers at a medium energy EIC (the proposed U.S. designs) and in large numbers at the LHeC. We investigate the acceptances for these states, as a function of detector rapidity coverage. A large-acceptance detector is needed to cover the full range photon-nucleon collision energies produced at an EIC; a forward detector is required to observe vector mesons from the most energetic photon interactions, and thereby probe gluons at the lowest possible Bjorken-$x$ values.

    ↳ nucl-exhep-phnucl-thPRC(2019)·55 citations
21. 21*

    Vortex-like solutions and internal structures of covariant ideal magnetohydrodynamics

    Wojciech Florkowski🇵🇱 · Avdhesh Kumar🇵🇱 · Radoslaw Ryblewski🇵🇱

    We discuss a manifestly covariant formulation of ideal relativistic magnetohydrodynamics, which has been recently used in astrophysical and heavy-ion contexts, and compare it to other similar frameworks. We show that the covariant equations allow for stationary vortex-like solutions that represent generalizations of the perfect-fluid solutions describing systems in global equilibrium with rotation. Such solutions are further used to demonstrate that inhomogeneous Maxwell equations, implicitly included in the covariant framework, may generate very large electric charge densities. This suggests that solutions of the covariant formulation may violate in some cases the assumptions of standard ideal magnetohydrodynamics. Furthermore, we show that the flow four-vector and conserved currents obtained in the covariant approach are usually not related to each other, which hinders kinetic-theory interpretation of the obtained results.

    ↳ nucl-thhep-phEPJA(2018)·8 citations
22. 22*

    Polar polarization: a new method for polarimetry analysis

    D. Izraeli (1)🇮🇱 · I. Mardor (1,2)🇮🇱 · E.O. Cohen (1)🇮🇱 · M. Duer (1)🇮🇱 · T.Y. Izraeli (3) · I. Korover (1,4)🇮🇱 · J. Lichtenstadt (1)🇮🇱 · E. Piasetzky (1) ((1) School of Physics and Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel., (2) Soreq NRC, Yavne 81800, Israel., (3) Guardian Optical Technologies, Derech Hashalom 7, Tel Aviv 6789208, Israel., (4) Department of Physics, NRCN, P.O. Box 9001, Beer-Sheva 8419001, Israel.)🇮🇱

    We present a novel analysis method for measurements of polarization transferred in $A(\vec{e},e^{\prime }\vec{N})$ experiments, which can be applied to other kinds of polarization measurements as well. In this method the polarization transfer components are presented in spherical coordinates using an efficient likelihood numerical maximization based on an analytic derivation. We also propose a formalism that accounts for multi-parameter models, and which yields a smooth and continuous representation of the data (rather than using standard binning). Applying this method on simulated data generates results with reduced statistical and systematic uncertainties and enables revealing physical information that is lost in standard binning of the data. The obtained results can be compared easily to theoretical models and other measurements. Furthermore, CPU time is significantly reduced using this method.

    ↳ nucl-thhep-phnucl-exJINST(2018)·2 citations
23. 23*

    Cosmological Tests With Strong Gravitational Lenses using Gaussian Processes

    Manoj K. Yennapureddy🇺🇸 · Fulvio Melia🇺🇸

    Strong gravitational lenses provide source/lens distance ratios D_obs useful in cosmological tests. Previously, a catalog of 69 such systems was used in a one-on-one comparison between the standard model, LCDM, and the R_h=ct universe, which has thus far been favored by the application of model selection tools to many other kinds of data. But in that work, the use of model parametric fits to the observations could not easily distinguish between these two cosmologies, in part due to the limited measurement precision. Here, we instead use recently developed methods based on Gaussian Processes (GP), in which D_obs may be reconstructed directly from the data without assuming any parametric form. This approach not only smooths out the reconstructed function representing the data, but also reduces the size of the 1-sigma confidence regions, thereby providing greater power to discern between different models. With the current sample size, we show that analyzing strong lenses with a GP approach can definitely improve the model comparisons, producing probability differences in the range ~10-30%. These results are still marginal, however, given the relatively small sample. Nonetheless, we conclude that the probability of R_h=ct being the correct cosmology is somewhat higher than that of LCDM, with a degree of significance that grows with the number of sources in the subsamples we consider. Future surveys will significantly grow the catalog of strong lenses and will therefore benefit considerably from the GP method we describe here. In addition, we point out that if the R_h=ct universe is eventually shown to be the correct cosmology, the lack of free parameters in the study of strong lenses should provide a remarkably powerful tool for uncovering the mass structure in lensing galaxies.

    ↳ astro-ph.COastro-ph.GAastro-ph.HEgr-qc+1EPJC(2018)·15 citations
24. 24*

    Exploring neutrino mass and mass hierarchy in the scenario of vacuum energy interacting with cold dark matter

    Rui-Yun Guo🇨🇳 · Jing-Fei Zhang🇨🇳 · Xin Zhang🇨🇳

    We investigate the constraints on total neutrino mass in the scenario of vacuum energy interacting with cold dark matter. We focus on two typical interaction forms, i.e., $Q=\beta H{\rho }_{\mathrm{c}}$ and $Q=\beta H{\rho }_{\Lambda }$. To avoid the occurrence of large-scale instability in interacting dark energy cosmology, we adopt the parameterized post-Friedmann approach to calculate the perturbation evolution of dark energy. We employ observational data, including the Planck cosmic microwave background temperature and polarization data, baryon acoustic oscillation data, a JLA sample of type Ia supernovae observation, direct measurement of the Hubble constant, and redshift space distortion data. We find that, compared with those in the $\Lambda$CDM model, much looser constraints on $\sum m_{\nu }$ are obtained in the $Q=\beta H{\rho }_{\mathrm{c}}$ model, whereas slightly tighter constraints are obtained in the $Q=\beta H{\rho }_{\Lambda }$ model. Consideration of the possible mass hierarchies of neutrinos reveals that the smallest upper limit of $\sum m_{\nu }$ appears in the degenerate hierarchy case. By comparing the values of ${\chi }_{\min }^2$, we find that the normal hierarchy case is favored over the inverted one. In particular, we find that the difference $\Delta {\chi }_{\min }^2\equiv {\chi }_{\mathrm{IH};\min }^2-{\chi }_{\mathrm{NH};\min }^2>2$ in the $Q=\beta H{\rho }_{\mathrm{c}}$ model. In addition, we find that $\beta =0$ is consistent with the current observations in the $Q=\beta H{\rho }_{\mathrm{c}}$ model, and $\beta <0$ is favored at more than the $1\sigma$ level in the $Q=\beta H{\rho }_{\Lambda }$ model.

    ↳ astro-ph.COgr-qchep-phCPC(2018)·67 citations
25. 25*

    Inertial Symmetry Breaking

    Christopher T. Hill🇺🇸

    We review and expand upon recent work demonstrating that Weyl invariant theories can be broken "inertially," which does not depend upon a potential. This can be understood in a general way by the "current algebra" of these theories, independently of specific Lagrangians. Maintaining the exact Weyl invariance in a renormalized quantum theory can be accomplished by renormalization conditions that refer back to the VEV's of fields in the action. We illustrate the computation of a Weyl invariant Coleman-Weinberg potential that breaks a U(1) symmetry together,with scale invariance.

    ↳ hep-thastro-ph.COhep-ph12 citations
26. 26*

    Analytical Infrared Limit of Nonlinear Thomson Scattering Including Radiation Reaction

    A. Di Piazza🇩🇪

    If an electric charge is accelerated by a sufficiently intense electromagnetic field, the effects of the radiation emitted by the charge on the charge dynamics (radiation reaction) cannot be ignored. Here we show that classical radiation-reaction effects alter qualitatively and quantitatively the infrared behavior of the spectrum of the radiation emitted by an electron in the presence of an intense electromagnetic plane wave (nonlinear Thomson scattering). An analytical expression of the infrared limit of nonlinear Thomson scattering is provided, which includes radiation-reaction effects and is valid for an arbitrary plane wave. Apart from their own conceptual importance and as a signature of classical radiation reaction, these results provide the limiting expression of the corresponding and yet unknown exact infrared behavior of strong-field QED in an intense plane wave.

    ↳ physics.plasm-phhep-phPLB(2018)·23 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.