Mon·May 21, 2018Monday·May 21, 2018

1. 01*

   Investigating the scalar sector of left-right symmetric models with leptonic probes

   Debasish Borah🇮🇳 · Benjamin Fuks🇫🇷 · Deepanjali Goswami🇮🇳 · P. Poulose🇮🇳

   We investigate the potential collider signatures of singly-charged and doubly-charged Higgs bosons such as those arising in minimal left-right symmetric models. Focusing on multileptonic probes in the context of the high-luminosity run of the Large Hadron Collider, we separately assess the advantages of the four-leptonic and trileptonic final states for a representative benchmark setup designed by considering a large set of experimental constraints. Our study establishes possibilities of identifying singly-charged and doubly-charged scalars at the Large Hadron Collider with a large significance, for luminosity goals expected to be reached during the high-luminosity phase of the Large Hadron Collider. We generalise our results and demonstrate that existing limits can in principle be pushed much further in the heavy mass regime.

   hep-phPRD(2018)·10 citations
2. 02*

   Kinematic reconstruction of $Z/H\to \tau \tau$ decay in proton-proton collisions

   Vladimir Cherepanov🇫🇷 · Alexander Zotz🇩🇪

   The knowledge of $\tau$ lepton kinematic and kinematic of the $\tau$ pair in the decay $Z/H\to \tau \tau$ is essential for various analysis at LHC. However, the reconstruction of the whole kinematic of the $\tau$ decay is a challenging task, since in every $\tau$ decay at least one neutrino is present in the final state which escapes detection. In this paper a kinematic technique (Global Event Fit) to estimate the momentum escaped with neutrinos and hence the full momentum of the $\tau$ lepton pair is described. The algorithm is based on iterative minimization of the likelihood with constrains derived from all available kinematic information on the decay. The method requires the direction of at least one $\tau$ lepton to be well defined and therefore the method can be applied to the decays $Z/H\to \tau \tau \to X+a_1\nu$ with $a_1$ resonance decaying into three charged pions.

   hep-phhep-ex13 citations
3. 03*

   Non-Abelian strings and domain walls in two Higgs doublet models

   Minoru Eto🇯🇵 · Masafumi Kurachi🇯🇵 · Muneto Nitta🇯🇵

   Contrary to the standard model that does not admit topologically nontrivial solitons, two Higgs doublet models admit topologically stable vortex strings and domain walls. We numerically confirm the existence of a topological $Z$-string confining fractional $Z$-flux inside. We show that topological strings at $\sin {\theta }_W=0$ limit reduce to non-Abelian strings which possess non-Abelian moduli $S^2$ associated with spontaneous breakdown of the $SU(2)$ custodial symmetry. We numerically solve the equations of motion for various parameter choices. It is found that a gauging $U(1{)}_Y$ always lowers the tension of the $Z$-string while it keeps that of the $W$-string. On the other hand, a deformation of the Higgs potential is either raising or lowering the tensions of the $Z$-string and $W$-string. We numerically obtain an effective potential for the non-Abelian moduli $S^2$ for various parameter deformations under the restriction $\tan \beta =1$. It is the first time to show that there exists a certain parameter region where the topological $W$-string can be the most stable topological excitation, contrary to conventional wisdom of electroweak theories. We also obtain numerical solutions of composites of the string and domain walls in a certain condition.

   hep-phhep-thJHEP(2018)·42 citations
4. 04*

   Analysis of the semileptonic $B\to K_1{\ell }^{+}{\ell }^{-}$transitions and non-leptonic $B\to K_1\gamma$ decay in the AdS/QCD correspondence

   S. Momeni🇮🇷 · R. Khosravi🇮🇷

   We consider the axial-vector mesons $K_1(1270)$ and $K_1(1400)$ as a mixture of two ${|}^3{P}_1⟩$ and ${|}^1{P}_1⟩$ states with the mixing angle $\theta$ that equal to $(-34\pm 13{)}^{\circ }$. We calculate the light-front distribution amplitudes (LFDAs) and decay constant formulas for both the axial-vector mesons $K_1$ in the AdS/QCD correspondence. The transition form factors of the semileptonic $B\to K_1$ decays are derived in terms of the LFDAs for $K_1$ mesons. Using these form factors and decay constant values, the differential branching ratios of $B\to K_1(1270,1400){\ell }^{+}{\ell }^{-}$,~$\ell =\mu ,\tau$ transitions are plotted with respect to the four-momentum transfer squared, $q^2$. In addition, the branching ratio values of these decays and the non-leptonic $B\to K_1(1270,1400)\gamma$ decays are estimated. A comparison is made between our results for the branching ratios of $B\to K_1(1270,1400)\gamma$ decays in the AdS/QCD model and predictions obtained from the light-cone sum rules (LCSR) as well as the experimental values. Finally, the forward-backward asymmetries for the aforementioned semileptonic decays are plotted on $q^2$ in both the AdS/QCD correspondence and two Higgs doublet model (2HDM) in order to test the standard model (SM) and search for the new physics (NP).

   hep-phEPJC(2018)·9 citations
5. 05*

   Three-Body $B_{(s)}^0$ to $\varphi {\pi }^{+}{\pi }^{-}$ Decays

   T. Estabar🇮🇷 · H. Mehraban🇮🇷

   We interest to investigate of the three-body decays of $B^0$ meson to $\varphi {\pi }^{+}{\pi }^{-}$ and $B_s^0$ meson to $\varphi {\pi }^{+}{\pi }^{-}$. Hadronic three-body decays include both nonresonant and resonant contributions, on the basis of the factorization hypothesis. In this analysis, resonant structure is exhibited only in the ${\pi }^{+}{\pi }^{-}$ channel which the resonant contribution can be described by S-wave, P-wave and D-wave ${\pi }^{+}{\pi }^{-}$ contribution from $f_0(980)$, $\rho$ and $f_2$ mesons and other possible resonance. Therefore, the theoretical values at the scale $m_b$ are $(1.69\pm 0.19)\times 10^{-7}$ and $(3.28\pm 0.17)\times 10^{-6}$, while the experimental results of them are $(1.82\pm 0.25)\times 10^{-7}$ and $(3.48\pm 0.23)\times 10^{-6}$, respectively. Comparing computation analysis values with experimental values show that our results at the scale ${\mu }_b$ are in agreement with them.

   hep-phPTEP(2018)·1 citation
6. 06*

   A new decay mode of higher charmonium

   Li-Ye Xiao🇨🇳 · Xin-Zhen Weng🇨🇳 · Qi-Fang Lü🇨🇳 · Xian-Hui Zhong🇨🇳 · Shi-Lin Zhu🇨🇳

   We calculate the ${\Lambda }_c{\bar{\Lambda }}_c$ partial decay width of the excited vector charmonium states around 4.6 GeV with the quark pair creation model. We find that the partial decay width of the ${\Lambda }_c{\bar{\Lambda }}_c$ mode can reach up to several MeV for $\psi (4S,5S,6S)$. In contrast, the partial ${\Lambda }_c{\bar{\Lambda }}_c$ decay width of the states $\psi (3D,4D,5D)$ is less than one MeV. If the enhancement $Y(4630)$ reported by the Belle Collaboration in ${\Lambda }_c{\bar{\Lambda }}_c$ invariant-mass distribution is the same structure as $Y(4660)$, the $Y(4660)$ resonance is most likely to be a $S$-wave charmonium state.

   hep-phEPJC(2018)·13 citations
7. 07*

   Predictive neutrino mass textures with origin of flavor symmetries

   Tatsuo Kobayashi🇯🇵 · Takaaki Nomura🇰🇷 · Hiroshi Okada🇹🇼

   We investigate origins of predictive one-zero neutrino mass textures in a systematic way. Here we search Abelian continuous(discrete) global symmetries, and non-Abelian discrete symmetries, and show how to realize these neutrino masses. Then we propose a concrete model involving a dark matter candidate and an extra gauge boson, and show their phenomenologies.

   hep-phPRD(2018)·9 citations
8. 08*

   Contribution of constituent quark model $c\bar{s}$ states to the dynamics of the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ resonances

   M. Albaladejo🇪🇸 · P. Fernandez-Soler🇪🇸 · J. Nieves🇪🇸 · P. G. Ortega🇪🇸

   The masses of the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ resonances lie below the $DK$ and $D^{\ast }K$ thresholds respectively, which contradicts the predictions of naive quark models and points out to non-negligible effects of the $D^{(\ast )}K$ loops in the dynamics of the even-parity scalar ($J^{\pi }=0^{+}$) and axial-vector ($J^{\pi }=1^{+}$) $c\bar{s}$ systems. Recent lattice QCD studies, incorporating the effects of the $D^{(\ast )}K$ channels, analyzed these spin-parity sectors and correctly described the $D_{s0}^{\ast }(2317)-D_{s1}(2460)$ mass splitting. Motivated by such works, we study the structure of the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ resonances in the framework of an effective field theory consistent with heavy quark spin symmetry, and that incorporates the interplay between $D^{(\ast )}K$ meson-meson degrees of freedom and bare P-wave $c\bar{s}$ states predicted by constituent quark models. We extend the scheme to finite volumes and fit the strength of the coupling between both types of degrees of freedom to the available lattice levels, which we successfully describe. We finally estimate the size of the $D^{(\ast )}K$ two-meson components in the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ resonances, and we conclude that these states have a predominantly hadronic-molecular structure, and that it should not be tried to accommodate these mesons within $c\bar{s}$ constituent quark model patterns.

   hep-phEPJC(2018)·76 citations
9. 09*

   Rapidity gap survival factors caused by remnant fragmentation for $W^{+}{W}^{-}$ pair production via ${\gamma }^{\ast }{\gamma }^{\ast }\to W^{+}{W}^{-}$ subprocess with photon transverse momenta

   Laurent Forthomme🇺🇸 · Marta Łuszczak🇵🇱 · Wolfgang Schäfer🇵🇱 · Antoni Szczurek🇵🇱

   We calculate the cross section for $pp\to W^{+}{W}^{-}$ in the recently developed $k_{\mathrm{T}}$-factorisation approach, including transverse momenta of the virtual photons. We focus on processes with single and double proton dissociation. First we discuss the gap survival on the parton level as due to the emission of extra jet. Both the role of valence and sea contributions is discussed. The hadronisation of proton remnants is performed with {PYTHIA 8} string fragmentation model, assuming a simple quark-diquark model for proton. Highly excited remnant systems hadronise producing particles that can be vetoed in the calorimeter. We calculate associated effective gap survival factors. The gap survival factors depend on the process, mass of the remnant system and collision energy. The rapidity gap survival factor due to remnant fragmentation for double dissociative (DD) collisions ($S_{R,DD}$) is smaller than that for single dissociative (SD) process ($S_{R,SD}$). We observe the approximate factorisation $S_{R,DD}\approx (S_{R,SD}{)}^2$, however it is expected that this property will be violated by soft rescattering effects not accounted for in this letter.

   hep-phhep-exPLB(2019)·21 citations
10. 10*

    Transverse momentum dependent transversely polarized distributions at next-to-next-to-leading-order

    Daniel Gutierrez-Reyes🇪🇸 · Ignazio Scimemi🇪🇸 · Alexey Vladimirov🇩🇪

    We calculate the matching of the transversity and pretzelosity transverse momentum dependent distributions (TMD) on transversity collinear distribution at the next-to-next-to-leading order (NNLO). We find that the matching coefficient for pretzelosity distribution is zero, despite the matrix element for it is nontrivial. This result suggests that the pretzelosity matches a twist-4 distribution. The matching for transversity TMD distributions is provided for both parton distribution functions and fragmentation functions cases.

    hep-phnucl-thJHEP(2018)·47 citations
11. 11*

    Dynamical Hadrons

    V. R. Debastiani🇪🇸 · E. Oset🇪🇸 · J. M. Dias🇧🇷 · Wei-Hong Liang🇨🇳

    In this talk I briefly review the theory of resonances dynamically generated from hadron-hadron scattering, sometimes referred to as "molecules"S. I give some classical examples of meson-meson and meson-baryon systems, as well as a few examples of different approaches to describe the interaction between hadrons. To conclude, I comment on a few recent works that suggest that some of the five new narrow ${\Omega }_c$ states, recently discovered by the LHCb collaboration, can be interpreted as meson-baryon molecules.

    hep-phActa Phys.Polon.Supp.(2018)·0 citations
12. 12*

    Radion-Higgs Mixing in 2HDMs

    Marco Merchand🇺🇸 · Marc Sher🇺🇸 · Keith Thrasher🇺🇸

    We study the custodial Randall-Sundrum model with two Higgs doublets localized in the $\text{TeV}$ brane. The scalar potential is CP- conserving and has a softly broken $Z_2$ symmetry. In the presence of a curvature-scalar mixing term ${\xi }_{ab}\mathcal{R}{\Phi }_a^{†}{\Phi }_b$ the radion that stabilizes the extra dimension now mixes with the two CP-even neutral scalars $h$ and $H$. A goodness of fit of the LHC data on the properties of the light Higgs is performed on the parameter space of the type-I and type-II models. LHC direct searches for heavy scalars in different decay channels can help distinguish between the radion and a heavy Higgs. The most important signatures involve the ratio of heavy scalar decays into $b$ quark pairs to those into $Z$ pairs, as well as the decay of the scalar (pseudoscalar) into a $Z$ plus a pseudoscalar (scalar).

    hep-phJHEP(2018)·2 citations
13. 13*

    Listening to the Universe through Indirect Detection

    Nicholas L. Rodd🇺🇸

    Indirect detection is the search for the particle nature of dark matter with astrophysical probes. Manifestly, it exists right at the intersection of particle physics and astrophysics, and the discovery potential for dark matter can be greatly extended using insights from both disciplines. This thesis provides an exploration of this philosophy. On the one hand, I will show how astrophysical observations of dark matter, through its gravitational interaction, can be exploited to determine the most promising locations on the sky to observe a particle dark matter signal. On the other, I demonstrate that refined theoretical calculations of the expected dark matter interactions can be used disentangle signals from astrophysical backgrounds. Both of these approaches will be discussed in the context of general searches, but also applied to the case of an excess of photons observed at the center of the Milky Way. This galactic center excess represents both the challenges and joys of indirect detection. Initially thought to be a signal of annihilating dark matter at the center of our own galaxy, it now appears more likely to be associated with a population of millisecond pulsars. Yet these pulsars were completely unanticipated, and highlight that indirect detection can lead to many new insights about the universe, hopefully one day including the particle nature of dark matter.

    hep-ph1 citation
14. 14*

    Unitarity constraints on general scalar couplings with SARAH

    Mark D. Goodsell🇫🇷 · Florian Staub🇩🇪

    We present an update of the Mathematica package SARAH to calculate unitarity constraints in BSM models. The new functions can perform an analytical and numerical calculation of the two-particle scattering matrix of (uncoloured) scalars. We do not make use of the simplifying assumption of a very large scattering energy, but include all contributions which could become important at small energies above the weak scale. This allows us to constrain trilinear scalar couplings. However, it can also modify (weakening or strengthening) the constraints on quartic couplings, which we show via the example of a singlet extended Standard Model.

    hep-phEPJC(2018)·102 citations
15. 15*

    Unitarity constraints in triplet extensions beyond the large s limit

    Manuel E. Krauss🇩🇪 · Florian Staub🇩🇪

    Triplet extensions are attractive alternatives to the standard model (SM) of particle physics. While models with only one triplet are highly constrained by electroweak precision observables, this is not necessarily the case once several triplets are present as in the Georgi-Machacek model. As in all other BSM models, the parameter space of triplet extensions is constrained by the condition that perturbative unitarity is not violated. For this purpose, limits on the eigenvalues of the scalar $2\to 2$ scattering matrix are set. It is very common in the BSM literature that the scattering matrix is calculated under one crucial assumption: the scattering energy s is so large that only point interactions involving quartic couplings provide non-negligible contributions. However, it is not given that this approximation is always valid - in fact, diagrams involving propagators can play an important role. We discuss at the examples of (i) the SM model extended by a real triplet, (ii) the Y = 1 triplet extension of the SM, and (iii) the Georgi-Machacek model, how the tree-level unitarity constraints are affected once the large s approximation is given up. For all models we find that the impact of (effective) cubic couplings can be crucial.

    hep-phPRD(2018)·23 citations
16. 16*

    Improved unitarity constraints in Two-Higgs-Doublet-Models

    Mark D. Goodsell🇫🇷 · Florian Staub🇩🇪

    Two-Higgs-Doublet-Models (THDMs) are among the simplest extensions of the standard model and are intensively studied in the literature. Using on-shell parameters such as the masses of the additional scalars as input, corresponds often to large quartic couplings in the underlying Lagrangian. Therefore, it is important to check if these couplings are for instance in agreement with perturbative unitarity. The common approach for doing this check is to consider the two-particle scattering matrix of scalars in the large centre-of-mass energy limit where only point interactions contribute. We show that this is not always a valid approximation: the full calculation including all tree-level contributions at finite energy can lead to much more stringent constraints. We show how the allowed regions in the parameter space are affected. In particular, the light Higgs window with a second Higgs below 125 GeV completely closes for large values of the $Z_2$ breaking parameter $|M_{12}|$. We also compare against the loop corrected constraints, which use also the large $\sqrt{s}$ approximation, and find that (effective) cubic couplings are often more important than radiative corrections.

    hep-phPLB(2019)·34 citations
17. 17*

    Parameter-Independent Quark Mass Relation in the U(3)$\times$U(3)${}^{\prime }$ Model

    Yoshio Koide🇯🇵 · Hiroyuki Nishiura🇯🇵

    Recently, we have proposed a quark mass matrix model based on U(3)$\times$U(3)${}^{\prime }$ family symmetry, in which up- and down-quark mass matrices $M_u$ and $M_d$ are described only by complex parameters $a_u$ and $a_d$, respectively. When we use charged lepton masses as additional input values, we can successfully obtain predictions for quark masses and Cabibbo-Kobayashi-Maskawa mixing. Since we have only one complex parameter $a_q$ for each mass matrix $M_q$, we can obtain a parameter-independent mass relation by using three equations for $\mathrm{Tr}[H_q]$, $\mathrm{Tr}[H_q{H}_q]$ and $\det H_q$, where $H_q\equiv M_q{M}_q^{†}$ ($q=u,d$). In this paper, we investigate its parameter-independent feature of the quark mass relation in the model.

    hep-phMod.Phys.Lett.A(2018)·1 citation
18. 18*

    A Realistic U(2) Model of Flavor

    Matthias Linster🇩🇪 · Robert Ziegler🇩🇪

    We propose a simple $U(2)$ model of flavor compatible with an $SU(5)$ GUT structure. All hierarchies in fermion masses and mixings arise from powers of two small parameters that control the $U(2)$ breaking. In contrast to previous $U(2)$ models this setup can be realized without supersymmetry and provides an excellent fit to all SM flavor observables including neutrinos. We also consider a variant of this model based on a $D_6\times U(1{)}_F$ flavor symmetry, which closely resembles the $U(2)$ structure, but allows for Majorana neutrino masses from the Weinberg operator. Remarkably, in this case one naturally obtains large mixing in the lepton sector from small mixing in the quark sector. The model also offers a natural option for addressing the Strong CP Problem and Dark Matter by identifying the Goldstone boson of the $U(1{)}_F$ factor as the QCD axion.

    hep-phJHEP(2018)·74 citations
19. 19*

    Gravitino Decay in High Scale Supersymmetry with R-parity Violation

    Emilian Dudas🇫🇷 · Tony Gherghetta🇺🇸 · Kunio Kaneta🇺🇸 · Yann Mambrini🇫🇷 · Keith A. Olive🇺🇸

    We consider the effects of R-parity violation due to the inclusion of a bilinear ${\mu }^{\prime }L{H}_u$ superpotential term in high scale supersymmetric models with an EeV scale gravitino as dark matter. Although the typical phenomenological limits on this coupling (e.g. due to lepton number violation and the preservation of the baryon asymmetry) are relaxed when the supersymmetric mass spectrum is assumed to be heavy (in excess of the inflationary scale of $3\times 10^{13}$ GeV), the requirement that the gravitino be sufficiently long-lived so as to account for the observed dark matter density, leads to a relatively strong bound on ${\mu }^{\prime }\lesssim 20$ GeV. The dominant decay channels for the longitudinal component of the gravitino are $Z\nu ,W^{\pm }{l}^{\mp }$, and $h\nu$. To avoid an excess neutrino signal in IceCube, our limit on ${\mu }^{\prime }$ is then strengthened to ${\mu }^{\prime }\lesssim 50$ keV. When the bound is saturated, we find that there is a potentially detectable flux of mono-chromatic neutrinos with EeV energies.

    hep-phastro-ph.HEPRD(2018)·68 citations
20. 20*

    Thermal corrections to the gluon magnetic Debye mass

    Alejandro Ayala🇲🇽 · Jorge David Castaño-Yepes🇲🇽 · C. A. Dominguez🇿🇦 · S. Hernandez-Ortiz🇲🇽 · L. A. Hernandez🇿🇦 · M. Loewe🇨🇱 · D. Manreza Paret🇲🇽 · R. Zamora🇨🇱

    We compute the gluon polarization tensor in a thermo-magnetic environment in the strong magnetic field limit at zero and high temperature. The magnetic field effects are introduced using Schwinger's proper time method. Thermal effects are computed in the HTL approximation. At zero temperature, we reproduce the well-known result whereby for a non-vanishing quark mass, the polarization tensor reduces to the parallel structure and its coefficient develops an imaginary part corresponding to the threshold for quark-antiquark pair production. This coefficient is infrared finite and simplifies considerably when the quark mass vanishes. Keeping always the field strength as the largest energy scale, in the high temperature regime we analyze two complementary hierarchies of scales: $q^2\ll m_f^2\ll T^2$ and $m_f^2\ll q^2\ll T^2$. In the latter, we show that the polarization tensor is infrared finite as $m_f$ goes to zero. In the former, we discuss the thermal corrections to the magnetic Debye mass.

    hep-phhep-thnucl-thRev.Mex.Fis.(2020)·26 citations
21. 21*

    Dark matter and long-lived particles at the LHC

    Jan Heisig🇩🇪

    While the paradigm of a weakly interacting massive particle (WIMP) has guided our search strategies for dark matter in the past decades, their null-results have stimulated growing interest in alternative explanations pointing towards non-standard signatures. In this article we discuss the phenomenology of dark matter models that predict long-lived particle at the LHC. We focus on models with a $Z_2$-odd dark sector where - in decreasing order of the dark matter coupling - a coannihilation, conversion-driven freeze-out or superWIMP/freeze-in scenario could be realized.

    hep-ph4 citations
22. 22*

    The Stochastic Axion Scenario

    Peter W. Graham🇺🇸 · Adam Scherlis🇺🇸

    For the minimal QCD axion model it is generally believed that overproduction of dark matter constrains the axion mass to be above a certain threshold, or at least that the initial misalignment angle must be tuned if the mass is below that threshold. We demonstrate that this is incorrect. During inflation, if the Hubble scale is low, the axion tends toward an equilibrium. This means the minimal QCD axion can naturally give the observed dark matter abundance in the entire lower part of the mass range, down to masses $\sim 10^{-12}$ eV (or $f_a$ up to almost the Planck scale). The axion abundance is generated by quantum fluctuations of the field during inflation. This mechanism generates cold dark matter with negligible isocurvature perturbations. In addition to the QCD axion, this mechanism can also generate a cosmological abundance of axion-like particles and other light fields.

    hep-phhep-thPRD(2018)·222 citations
23. 23*

    Forward modelling of quasar light curves and the cosmological matter power spectrum on milliparsec scales

    Mansour Karami🇨🇦 · Niayesh Afshordi🇨🇦 · Jesús Zavala🇮🇸

    We devise an optimal method to measure the temporal power spectrum of the lensing and intrinsic fluctuations of multiply-imaged strongly lensed quasar light curves, along with the associated time delays. The method is based on a Monte-Carlo Markov Chain (MCMC) sampling of a putative gaussian likelihood, and accurately recovers the input properties of simulated light curves, as well as the "Time Delay Challenge". We apply this method to constrain the dimensionless cosmological (non-linear) matter power spectrum on milliparsec scales (comparable to the size of the solar system), to ${\Delta }_{\mathrm{NL}}^2<4\times 10^7$ at $k_{\mathrm{NL}}\sim 10^3{\mathrm{pc}}^{-1}$. Using a semi-analytic nonlinear clustering model which is calibrated to simulations, the corresponding constraint on the primordial (linear) scalar power spectrum is ${\mathcal{P}}_{\mathcal{R}}<3\times 10^{-9}$ at $k_{\mathrm{L}}\sim$ 3 pc${}^{-1}$. This is the strongest constraint on primordial power spectrum at these scales, and is within an order of magnitude from the standard $\Lambda$CDM prediction. We also report measurements of temporal spectra for intrinsic variabilities of quasar light curves, which can be used to constrain the size of the emitting region in accretion disks. Future cadenced optical imaging surveys, such as LSST, should increase the number of observed strongly lensed quasars by 3 orders of magnitude and significantly improve these measurements, even though improvements in modelling quasar accretion and stellar microlensing are necessary.

    ↳ astro-ph.COastro-ph.IMhep-ph10 citations
24. 24*

    Dynamical and observational constraints on the Warm Little Inflaton scenario

    Mar Bastero-Gil🇪🇸 · Arjun Berera🇬🇧 · Rafael Hernandez-Jimenez🇬🇧 · Joao G. Rosa🇵🇹

    We explore the dynamics and observational predictions of the Warm Little Inflaton scenario, presently the simplest realization of warm inflation within a concrete quantum field theory construction. We consider three distinct types of scalar potentials for the inflaton, namely chaotic inflation with a quartic monomial potential, a Higgs-like symmetry breaking potential and a non-renormalizable plateau-like potential. In each case, we determine the parametric regimes in which the dynamical evolution is consistent for 50-60 e-folds of inflation, taking into account thermal corrections to the scalar potential and requiring, in particular, that the two fermions coupled directly to the inflaton remain relativistic and close to thermal equilibrium throughout the slow-roll regime and that the temperature is always below the underlying gauge symmetry breaking scale. We then compute the properties of the primordial spectrum of scalar curvature perturbations and the tensor-to-scalar ratio in the allowed parametric regions and compare them with Planck data, showing that this scenario is theoretically and observationally successful for a broad range of parameter values.

    ↳ astro-ph.COgr-qchep-phPRD(2018)·51 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.