Mon·Mar 5, 2018Monday·March 5, 2018

1. 01*

   Lepton Flavorful Fifth Force and Depth-dependent Neutrino Matter Interactions

   Mark B. Wise🇺🇸 · Yue Zhang🇺🇸

   We consider a fifth force to be an interaction that couples to matter with a strength that grows with the number of atoms. In addition to competing with the strength of gravity a fifth force can give rise to violations of the equivalence principle. Current long range constraints on the strength and range of fifth forces are very impressive. Amongst possible fifth forces are those that couple to lepton flavorful charges $L_e-L_{\mu }$ or $L_e-L_{\tau }$. They have the property that their range and strength are also constrained by neutrino interactions with matter. In this brief note we review the existing constraints on the allowed parameter space in gauged $U(1{)}_{L_e-L_{\mu },L_{\tau }}$. We find two regions where neutrino oscillation experiments are at the frontier of probing such a new force. In particular, there is an allowed range of parameter space where neutrino matter interactions relevant for long baseline oscillation experiments depend on the depth of the neutrino beam below the surface of the earth.

   hep-phhep-exJHEP(2018)·82 citations
2. 02*

   Constraining the $R$-symmetric chargino NLSP at the LHC

   Carlos Alvarado🇺🇸 · Antonio Delgado🇺🇸 · Adam Martin🇺🇸

   We present a phenomenological study of Dirac electroweakinos in a $U(1{)}_R$ extension of the MSSM with a strictly $R$-symmetric Higgs sector (MRSSM) and gauge-mediated supersymmetry breaking. One of the distinguishing features of the MRSSM is that the lightest chargino can be lighter than the lightest neutralino. Decays from the NLSP chargino to the gravitino LSP will produce exotic signals. We apply LHC-13 mass limits from both prompt and long-lived searches to the chargino NLSP regime of the MRSSM. Imposing the additional constraints coming from the 125 GeV Higgs and from the electroweak sector, regions of the parameter space are found where the gravitino LSP, chargino NLSP scenario survives all current bounds. We also show that the fine-tuning of the model can reach a level slightly better than sub-percent with our choice of parameters.

   hep-phPRD(2018)·26 citations
3. 03*

   Probing the Type-II Seesaw Mechanism through the Production of Higgs Bosons at a Lepton Collider

   Pankaj Agrawal🇮🇳 · Manimala Mitra🇮🇳 · Saurabh Niyogi🇮🇳 · Sujay Shil🇮🇳 · Michael Spannowsky🇬🇧

   We investigate the production and decays of doubly-charged Higgs bosons for the Type-II seesaw mechanism at an $e^{+}{e}^{-}$ collider with two center of mass energies, $\sqrt{s}=380$ GeV and 3 TeV, and analyze the fully hadronic final states in detail. Lower mass ranges can be probed during the 380 GeV run of the collider, while high mass ranges, which are beyond the 13 TeV Large Hadron Collider discovery reach, can be probed with $\sqrt{s}=3$ TeV. For such a heavy Higgs boson, the final decay products are collimated, resulting in fat-jets. We perform a substructure analysis to reduce the background and find that a doubly-charged Higgs boson in the mass range 800-1120 GeV can be discovered during the 3 TeV run, with integrated luminosity $\mathcal{L}\sim 95{\mathrm{fb}}^{-1}$ of data. For 380 GeV center of mass energy, we find that for the doubly-charged Higgs boson in the range 160-172 GeV, a $5\sigma$ significance can be achieved with only integrated luminosity $\mathcal{L}\sim 24{\mathrm{fb}}^{-1}$. Therefore, a light Higgs boson can be discovered immediately during the run of a future $e^{+}{e}^{-}$ collider.

   hep-phhep-exPRD(2018)·41 citations
4. 04*

   Stress-stress correlator in lambda phi^4 theory: Poles or a Cut?

   Guy D. Moore🇩🇪

   We explore the analytical properties of the traceless stress tensor 2-point function at zero momentum and small frequency (relevant for shear viscosity and hydrodynamic response) in hot, weakly coupled lambda phi^4 theory. We show that, rather than one or a small number of poles, the correlator has a cut along the negative imaginary frequency axis. We briefly discuss this result's relevance for constructing 2'nd order hydrodynamic models of hot relativistic field theories.

   hep-phJHEP(2018)·44 citations
5. 05*

   Gauged Peccei-Quinn Symmetry - A Case of Simultaneous Breaking of SUSY and PQ Symmetry

   Hajime Fukuda🇯🇵 · Masahiro Ibe🇯🇵 · Motoo Suzuki🇯🇵 · Tsutomu T. Yanagida🇯🇵

   Recently, a simple prescription to embed the global Peccei-Quinn (PQ) symmetry into a gauged $U(1)$ symmetry has been proposed. There, explicit breaking of the global PQ symmetry expected in quantum gravity are highly suppressed due to the gauged PQ symmetry. In this paper, we apply the gauged PQ mechanism to models where the global PQ symmetry and supersymmetry (SUSY) are simultaneously broken at around $\mathcal{O}(10^{11-12})$\,GeV. Such scenario is motivated by an intriguing coincidence between the supersymmetry breaking scale which explains the observed Higgs boson mass by the gravity mediated sfermion masses, and the PQ breaking scale which evades all the astrophysical and the cosmological constraints. As a concrete example, we construct a model which consists of a simultaneous supersymmetry/PQ symmetry breaking sector based on $SU(2)$ dynamics and an additional PQ symmetry breaking sector based on $SU(N)$ dynamics. We also show that new vector-like particles are predicted in the TeV range in the minimum model, which can be tested by the LHC experiments.

   hep-phJHEP(2018)·28 citations
6. 06*

   Non-thermal WIMP baryogenesis

   Ki-Young Choi🇰🇷 · Sin Kyu Kang🇰🇷 · Jongkuk Kim🇰🇷

   We propose a WIMP baryogensis achieved by the annihilation of non-thermally produced WIMPs from decay of heavy particles, which can result in low reheating temerature. Dark matter (DM) can be produced non-thermally during a reheating period created by the decay of long-lived heavy particle, and subsequently re-annihilate to lighter particles even after the thermal freeze-out. The re-annihilation of DM provides the observed baryon asymmetry as well as the correct relic density of DM. We investigate how wahout effects can affect the generation of the baryon asymmetry and study a model suppressing them. In this scenario, we find that DM can be heavy enough and its annihilation cross section can also be larger than that adopted in the usual thermal WIMP baryogenesis.

   hep-phastro-ph.COPLB(2018)·6 citations
7. 07*

   Searching for scalar boson decaying into light $Z^{\prime }$ boson at collider experiments in $U(1{)}_{L_{\mu }-L_{\tau }}$ model

   Takaaki Nomura🇰🇷 · Takashi Shimomura🇯🇵

   We study a model with $U(1{)}_{L_{\mu }-L_{\tau }}$ gauge symmetry and discuss collider searches for a scalar boson, which breaks $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry spontaneously, decaying into light $Z^{\prime }$ gauge boson. In this model, the new gauge boson, $Z^{\prime }$, with a mass lighter than $\mathcal{O}(100)$ MeV, plays a role in explaining the anomalous magnetic moment of muon via one-loop contribution. For the gauge boson to have such a low mass, the scalar boson, $\varphi$ with $\mathcal{O}(100)$ GeV mass appears associated with the symmetry breaking. We investigate experimental constraints on $U(1{)}_{L_{\mu }-L_{\tau }}$ gauge coupling, kinetic mixing, and mixing between the SM Higgs and $\varphi$. Then collider search is discussed considering $\varphi$ production followed by decay process $\varphi \to Z^{\prime }{Z}^{\prime }$ at the large hadron collider and the international linear collider. We also estimate discovery significance at the linear collider taking into account relevant kinematical cut effects.

   hep-phhep-exEPJC(2019)·23 citations
8. 08*

   Current and future constraints on Higgs couplings in the nonlinear Effective Theory

   Jorge de Blas🇮🇹 · Otto Eberhardt🇪🇸 · Claudius Krause🇪🇸

   We perform a Bayesian statistical analysis of the constraints on the nonlinear Effective Theory given by the Higgs electroweak chiral Lagrangian. We obtain bounds on the effective coefficients entering in Higgs observables at the leading order, using all available Higgs-boson signal strengths from the LHC runs 1 and 2. Using a prior dependence study of the solutions, we discuss the results within the context of natural-sized Wilson coefficients. We further study the expected sensitivities to the different Wilson coefficients at various possible future colliders. Finally, we interpret our results in terms of some minimal composite Higgs models.

   hep-phhep-exJHEP(2018)·106 citations
9. 09*

   Low-energy Effects of Lepton Flavour Universality Violation

   Claudia Cornella🇨🇭 · Ferruccio Feruglio🇮🇹 · Paride Paradisi🇮🇹

   The persisting anomalous data in semileptonic B-decays point towards New Physics models exhibiting large sources of Lepton Flavour Universality Violation. In this work we generalise previous studies by considering frameworks which include an enlarged set of semileptonic four-fermion operators invariant under the SM gauge group, with New Physics affecting mainly the third generation. We derive the low-energy effective Lagrangian including the leading electroweak corrections, mandatory to obtain reliable predictions. As a particularly interesting case, we analyse the scenario where the dominant New Physics effects are encoded in the Wilson coefficient C_9, as favoured by global fit analyses of b -> s data. We find that also in this case the stringent experimental bounds on Z-pole observables and tau decays challenge a simultaneous explanation of charged and neutral-current non-standard data.

   hep-phJHEP(2018)·36 citations
10. 10*

    Multi-jet merged top-pair production including electroweak corrections

    Christian Gütschow🇬🇧 · Jonas M. Lindert🇬🇧 · Marek Schönherr🇨🇭

    We present theoretical predictions for the production of top-quark pairs in association with jets at the LHC including electroweak (EW) corrections. First, we present and compare differential predictions at the fixed-order level for $t\bar{t}$ and $t\bar{t}+$jet production at the LHC considering the dominant NLO EW corrections of order $\mathcal{O}({\alpha }_S^2\alpha )$ and $\mathcal{O}({\alpha }_S^3\alpha )$ respectively together with all additional subleading Born and one-loop contributions. The NLO EW corrections are enhanced at large energies and in particular alter the shape of the top transverse momentum distribution, whose reliable modelling is crucial for many searches for new physics at the energy frontier. Based on the fixed-order results we motivate an approximation of the EW corrections valid at the percent level, that allows us to readily incorporate the EW corrections in the MEPS@NLO framework of Sherpa combined with OpenLoops. Subsequently, we present multi-jet merged parton-level predictions for inclusive top-pair production incorporating NLO QCD+EW corrections to $t\bar{t}$ and $t\bar{t}+$jet. Finally, we compare at the particle-level against a recent 8 TeV measurement of the top transverse momentum distribution performed by ATLAS in the lepton+jet channel. We find very good agreement between the Monte Carlo prediction and the data when the EW corrections are included.

    hep-phhep-exEPJC(2018)·90 citations
11. 11*

    Supernova 1987A Constraints on Sub-GeV Dark Sectors, Millicharged Particles, the QCD Axion, and an Axion-like Particle

    Jae Hyeok Chang🇺🇸 · Rouven Essig🇺🇸 · Samuel D. McDermott🇺🇸

    We consider the constraints from Supernova 1987A on particles with small couplings to the Standard Model. We discuss a model with a fermion coupled to a dark photon, with various mass relations in the dark sector; millicharged particles; dark-sector fermions with inelastic transitions; the hadronic QCD axion; and an axion-like particle that couples to Standard Model fermions with couplings proportional to their mass. In the fermion cases, we develop a new diagnostic for assessing when such a particle is trapped at large mixing angles. Our bounds for a fermion coupled to a dark photon constrain small couplings and masses <200 MeV, and do not decouple for low fermion masses. They exclude parameter space that is otherwise unconstrained by existing accelerator-based and direct-detection searches. In addition, our bounds are complementary to proposed laboratory searches for sub-GeV dark matter, and do not constrain several "thermal" benchmark-model targets. For a millicharged particle, we exclude charges between 10^(-9) to a few times 10^(-6) in units of the electron charge; this excludes parameter space to higher millicharges and masses than previous bounds. For the QCD axion and an axion-like particle, we apply several updated nuclear physics calculations and include the energy dependence of the optical depth to accurately account for energy loss at large couplings. We rule out a hadronic axion of mass between 0.1 and a few hundred eV, or equivalently bound the PQ scale between a few times 10^4 and 10^8 GeV, closing the hadronic axion window. For an axion-like particle, our bounds disfavor decay constants between a few times 10^5 GeV up to a few times 10^8 GeV. In all cases, our bounds differ from previous work by more than an order of magnitude across the entire parameter space. We also provide estimated systematic errors due to the uncertainties of the progenitor.

    hep-phastro-ph.COastro-ph.GAastro-ph.HE+1JHEP(2018)·598 citations
12. 12*

    Intrinsic charm contribution to the prompt atmospheric neutrino flux

    A. V. Giannini🇧🇷 · V. P. Goncalves🇧🇷 · F. S. Navarra🇧🇷

    In this work we investigate the impact of intrinsic charm on the prompt atmospheric neutrino flux. The color dipole approach to heavy quark production is generalized to include the contribution of processes initiated by charm quarks. The prompt neutrino flux is calculated assuming the presence of intrinsic charm in the wave function of the projetile hadron. The predictions are compared with previous color dipole results which were obtained taking into account only the process initiated by gluons. In addition, we estimate the atmospheric (conventional + prompt) neutrino flux and compare our predictions with the ICECUBE results for the astrophysical neutrino flux. Our results demonstrate that the contribution of the charm quark initiated process is non - negligible and that the prompt neutrino flux can be enhanced by a factor $\approx$ 2 at large neutrino energies if an intrinsic charm component is present in the proton wave function.

    hep-phastro-ph.HEnucl-thPRD(2018)·24 citations
13. 13*

    Precision constraints on radiative neutrino decay with CMB spectral distortion

    Jelle L. Aalberts🇳🇱 · Shin'ichiro Ando🇳🇱 · Wouter M. Borg🇳🇱 · Edwin Broeils🇳🇱 · Jennypher Broeils🇳🇱 · Stephen Broeils🇳🇱 · Bradley J. Kavanagh🇳🇱 · Gijs Leguijt🇳🇱 · Marnix Reemst🇳🇱 · Dylan R. van Arneman🇳🇱 · Hoang Vu🇳🇱

    We investigate the radiative decay of the cosmic neutrino background, and its impact on the spectrum of the cosmic microwave background (CMB) that is known to be a nearly perfect black body. We derive exact formulae for the decay of a heavier neutrino into a lighter neutrino and a photon, ${\nu }_j\to {\nu }_i+\gamma$, and of absorption as its inverse, ${\nu }_i+\gamma \to {\nu }_j$, by accounting for the precise form of the neutrino momentum distribution. Our calculations show that if the neutrinos are heavier than $\mathcal{O}(0.1)$ eV, the exact formulae give results that differ by $\sim$50%, compared with approximate ones where neutrinos are assumed to be at rest. We also find that spectral distortion due to absorption is more important for heavy neutrino masses (by a factor of $\sim$10 going from a neutrino mass of 0.01 eV to 0.1 eV). By analyzing the CMB spectral data measured with COBE-FIRAS, we obtain lower limits on the neutrino lifetime of ${\tau }_{12}\gtrsim 4\times 10^{21}$ s (95% C.L.) for the smaller mass splitting and ${\tau }_{13}\sim {\tau }_{23}\gtrsim 10^{19}$ s for the larger mass splitting. These represent up to one order of magnitude improvement over previous CMB constraints. With future CMB experiments such as PIXIE, these limits will improve by roughly 4 orders of magnitude. This translates to a projected upper limit on the neutrino magnetic moment (for certain neutrino masses and decay modes) of ${\mu }_{\nu }<3\times 10^{-11}{\mu }_B$, where ${\mu }_B$ is the Bohr magneton. Such constraints would make future precision CMB measurements competitive with lab-based constraints on neutrino magnetic moments.

    ↳ astro-ph.COhep-phPRD(2018)·34 citations
14. 14*

    Properties of the Top Quark

    Frederic Deliot🇫🇷 · Nicholas Hadley🇺🇸 · Stephen Parke🇺🇸 · Tom Schwarz🇺🇸

    The top quark is the heaviest known elementary particle, and it is often seen as a window to search for new physics processes in particle physics. A large program to study the top-quark properties has been performed both at the Tevatron and LHC colliders by the D0, CDF, ATLAS and CMS experiments. The most recent results are discussed in this review.

    ↳ hep-exhep-phAnn.Rev.Nucl.Part.Sci.(2014)·10 citations
15. 15*

    Dark energy from $\alpha$-attractors: phenomenology and observational constraints

    Carlos García-García🇪🇸 · Eric V. Linder🇺🇸 · Pilar Ruíz-Lapuente🇪🇸 · Miguel Zumalacárregui🇺🇸

    The possibility of linking inflation and late cosmic accelerated expansion using the $\alpha$-attractor models has received increasing attention due to their physical motivation. In the early universe, $\alpha$-attractors provide an inflationary mechanism compatible with Planck satellite CMB observations and predictive for future gravitational wave CMB modes. Additionally $\alpha$-attractors can be written as quintessence models with a potential that connects a power law regime with a plateau or uplifted exponential, allowing a late cosmic accelerated expansion that can mimic behavior near a cosmological constant. In this paper we study a generalized dark energy $\alpha$-attractor model. We thoroughly investigate its phenomenology, including the role of all model parameters and the possibility of large-scale tachyonic instability clustering. We verify the relation that $1+w\sim 1/\alpha$ (while the gravitational wave power $r\sim \alpha$) so these models predict that a signature should appear in either the primordial B-modes or in late time deviation from a cosmological constant. We constrain the model parameters with current datasets, including the cosmic microwave background (Planck 2015 angular power spectrum, polarization and lensing), baryon acoustic oscillations (BOSS DR12) and supernovae (Pantheon compressed). Our results show that expansion histories close to a cosmological constant exist in large regions of the parameter space, not requiring a fine-tuning of the parameters or initial conditions.

    ↳ astro-ph.COgr-qchep-phJCAP(2018)·53 citations
16. 16*

    Beta equilibrium in neutron star mergers

    Mark G. Alford🇺🇸 · Steven P. Harris🇺🇸

    We show that the commonly used criterion for beta equilibrium in neutrino-transparent dense nuclear matter becomes invalid as temperatures rise above 1 MeV. Such temperatures are attained in neutron star mergers. By numerically computing the relevant weak interaction rates we find that the correct criterion for beta equilibrium requires an isospin chemical potential that can be as large as 10-20 MeV, depending on the temperature at which neutrinos become trapped.

    ↳ nucl-thastro-ph.HEhep-phPRC(2018)·110 citations
17. 17*

    Probing vorticity structure in heavy-ion collisions by local $\Lambda$ polarization

    Xiao-Liang Xia🇨🇳 · Hui Li🇨🇳 · Zebo Tang🇨🇳 · Qun Wang🇨🇳

    We study the local structure of the vorticity field and the $\Lambda$ polarization in Au+Au collisions in the energy range $\sqrt{s_{\mathrm{NN}}}=7.7$--$200$ GeV and Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2760$ GeV using A Multi-Phase Transport (AMPT) model. We focus on the vorticity field arising from the non-uniform expansion of the fireball, which gives the circular structure of the transverse vorticity ${\mathbf{\omega }}_{\perp }=({\omega }_x,{\omega }_y)$ around the $z$ direction as well as the quadrupole pattern of the longitudinal vorticity ${\omega }_z$ in the transverse plane. As a consequence, the three components of the polarization vector $\mathbf{P}=(P_x,P_y,P_z)$ for $\Lambda$ hyperons show harmonic behaviors as $\mathrm{sgn}(Y)\sin {\varphi }_p$, $-\mathrm{sgn}(Y)\cos {\varphi }_p$, and $-\sin (2{\varphi }_p)$, where ${\varphi }_p$ and $Y$ are the azimuthal angle and rapidity in momentum space. These patterns of the local $\Lambda$ polarization are expected to be tested in future experiments.

    ↳ nucl-thhep-phPRC(2018)·209 citations
18. 18*

    QCD analysis of the ATLAS and CMS $W^{\pm }$ and $Z$ cross-section measurements and implications for the strange sea density

    A.M. Cooper-Sarkar🇬🇧 · K. Wichmann🇩🇪

    In the present paper, the ATLAS inclusive $W^{\pm }$ and $Z$ boson production data are analysed together with the CMS inclusive $W^{\pm }$ and $Z$ boson production data to investigate any possible tensions between the data sets and to determine the strange sea fraction, within the framework of a parton distribution function fit at next-to-next-to leading order in perturbative QCD.

    ↳ hep-exhep-phPRD(2018)·23 citations
19. 19*

    Constant-roll approach to non-canonical inflation

    Abolhassan Mohammadi🇮🇷 · Khaled Saaidi🇮🇷 · Haidar Sheikhahmadi🇿🇦

    The scenario of constant-roll inflation is studied where the inflaton is a scalar field with modified kinetic term, known as non-canonical scalar field. This modification leads to some changes in the slow-roll parameters, and also by taking the second slow-roll parameter as a constant, the differential equation for the Hubble parameter is altered as well. Assuming $\eta =\beta$ and reconsidering the perturbation equations makes it clear that there should be some modified terms in the scalar spectral index and amplitude of scalar perturbations. After finding the exact solution, the main perturbation parameters are obtained at the horizon crossing time. Then by plotting the $r-n_s$ diagram it is shown that for some specific values of $\beta$ one could find a good agreement with observational data. In addition, considering the attractor behavior of the model leads to this result that this feature could be appropriately satisfied.

    ↳ astro-ph.COhep-phPRD(2019)·47 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.