Thu·Nov 22, 2018Thursday·November 22, 2018

1. 01*

   Polarization of top and chargino from stop decay in natural SUSY

   Lei Wu🇨🇳 · Hang Zhou🇨🇳

   Top squark (stop) plays a crucial role in the naturalness of supersymmetry (SUSY) models, which has been extensively searched for in the LHC experiments. Due to the parity-violating couplings, top quark and chargino thus produced from stop decay are expected to be polarized. We investigate the polarization of top quark and chargino, from which we find that the mass differences between neutralino and stop/chargino can affect the degree of polarization of top quark/chargino in the stop decay. We then examine the top polarization effects on kinematics of stop decay in natural SUSY (NSUSY) at the LHC and the results show that several observables have the discriminating power for different polarized top quark at the LHC, which may be useful for testing the nature of stop couplings in NSUSY.

   hep-phPLB(2019)·9 citations
2. 02*

   Exploring fake solutions in the sterile neutrino sector at long-baseline experiments

   Sandhya Choubey🇮🇳 · Debajyoti Dutta🇮🇳 · Dipyaman Pramanik🇮🇳

   Active-sterile neutrino mixing is known to affect the neutrino oscillation probabilities at both short as well as long-baselines. In particular, constraints on active-sterile neutrino oscillation parameters can be obtained from long-baseline experiments such as T2HK and DUNE. We present here existence of fake solution in the appearance channel for the 3+1 scenario at long-baseline experiments. We show that the appearance probability is same for values of $\Delta m_{41}^2$ for which the fast oscillations are averaged out and for $\Delta m_{41}^2=(1/2)\Delta m_{31}^2$. The fake solution does not appear for the disappearance channel.

   hep-phEPJC(2019)·9 citations
3. 03*

   Towards a holographic quark-hadron continuity

   Kazem Bitaghsir Fadafan🇮🇷 · Farideh Kazemian🇮🇷 · Andreas Schmitt🇬🇧

   We study dense nuclear and quark matter within a single microscopic approach, namely the holographic Sakai-Sugimoto model. Nuclear matter is described via instantons in the bulk, and we show that instanton interactions are crucial for a continuous connection of chirally broken and chirally symmetric phases. The continuous path from nuclear to quark matter includes metastable and unstable stationary points of the potential, while the actual chiral phase transition remains of first order, as in earlier approximations. We show that the model parameters can be chosen to reproduce low-density properties of nuclear matter and observe a non-monotonic behavior of the speed of sound as a function of the baryon chemical potential, as suggested by constraints from QCD and astrophysics.

   hep-phhep-thnucl-thJHEP(2019)·44 citations
4. 04*

   Collider phenomenology of vector resonances in WZ scattering processes

   Rafael L. Delgado🇩🇪 · A.Dobado🇪🇸 · D.Espriu🇪🇸 · C.Garcia-Garcia🇪🇸 · M.J.Herrero🇪🇸 · X.Marcano🇫🇷 · J.J.Sanz-Cillero🇪🇸

   We study the production of vector resonances at the LHC via $WZ$ scattering processes and explore the sensitivities to these resonances for the expected future LHC luminosities. The electroweak chiral Lagrangian and the Inverse Amplitude Method (IAM) are used for analyzing a dynamically generated vector resonance, whose origin would be the (hypothetically strong) self interactions of the longitudinal gauge bosons, $W_L$ and $Z_L$. We implement the unitarized scattering amplitudes into a single model, the IAM-MC, that has been adapted to MadGraph~5. It is written in terms of the electroweak chiral Lagrangian and an additional effective Proca Lagrangian for the vector resonances, so that it reproduces the resonant behavior of the IAM and allows us to perform a realistic study of signal versus background at the LHC. We focus on the $pp\to WZjj$ channel, discussing first on the potential of the hadronic and semileptonic channels of the final $WZ$, and next exploring in more detail the clearest signals. These are provided by the leptonic decays of the gauge bosons, leading to a final state with $l_1^{+}{l}_1^{-}{l}_2^{+}\nu jj$, $l=e,\mu$, having a very distinctive signature, and showing clearly the emergence of the resonances with masses in the range of $1.5$-$2.5\mathrm{TeV}$, which we have explored.

   hep-phPoS(2019)·3 citations
5. 05*

   Impact of Fermionic Electroweak Multiplet Dark Matter on Vacuum Stability with One-loop Matching

   Jin-Wei Wang🇨🇳 · Xiao-Jun Bi🇨🇳 · Peng-Fei Yin🇨🇳 · Zhao-Huan Yu🇨🇳

   We investigate the effect of fermionic electroweak multiplet dark matter models on the stability of the electroweak vacuum using two-loop renormalization group equations (RGEs) and one-loop matching conditions. Such a treatment is crucial to obtain reliable conclusions, compared with one-loop RGEs and tree-level matching conditions. In addition, we find that the requirement of perturbativity up to the Planck scale would give strong and almost mass-independent constraints on the Yukawa couplings in the dark sector. We also evaluate these models via the idea of finite naturalness for the Higgs mass fine-tuning issue.

   hep-phPRD(2019)·18 citations
6. 06*

   Perturbativity constraints on $U(1{)}_{B-L}$ and left-right models and implications for heavy gauge boson searches

   Garv Chauhan🇺🇸 · P. S. Bhupal Dev🇺🇸 · Rabindra N. Mohapatra🇺🇸 · Yongchao Zhang🇺🇸

   We derive perturbativity constraints on beyond standard model scenarios with extra gauge groups, such as $SU(2)$ or $U(1)$, whose generators contribute to the electric charge, and show that there are both upper and lower limits on the additional gauge couplings, from the requirement that the couplings remain perturbative up to the grand unification theory (GUT) scale. This leads to stringent constraints on the masses of the corresponding gauge bosons and their collider phenomenology. We specifically focus on the models based on $SU(2{)}_L\times U(1{)}_{I_{3R}}\times U(1{)}_{B-L}$ and the left-right symmetric models based on $SU(2{)}_L\times SU(2{)}_R\times U(1{)}_{B-L}$, and discuss the implications of the perturbativity constraints for new gauge boson searches at current and future colliders. In particular, we find that the stringent flavor constraints in the scalar sector of left-right model set a lower bound on the right-handed scale $v_R\gtrsim 10$ TeV, if all the gauge and quartic couplings are to remain perturbative up to the GUT scale. This precludes the prospects of finding the $Z_R$ boson in the left-right model at the LHC, even in the high-luminosity phase, and leaves only a narrow window for the $W_R$ boson. A much broader allowed parameter space, with the right-handed scale $v_R$ up to $\simeq 87$ TeV, could be probed at the future 100 TeV collider.

   hep-phhep-exJHEP(2019)·33 citations
7. 07*

   Estimates of the $X(3872)$ Cross Section at a Hadron Collider

   Eric Braaten🇺🇸 · Li-Ping He🇺🇸 · Kevin Ingles🇺🇸

   The claim that the $X(3872)$ meson cannot be a charm-meson molecule because its prompt production cross section at hadron colliders is too large is based on an upper bound in terms of a cross section for producing charm-meson pairs. Assuming $X$ is sufficiently weakly bound, we derive an equality between the $X$ cross section and a charm-meson pair cross section that takes into account the threshold enhancement from the $X$ resonance. The cross section for producing $X$ is equal to that for producing $D^{\ast 0}{\bar{D}}^0$ integrated up to a relative momentum $k_{\max }=7.7{\gamma }_X$, where ${\gamma }_X$ is the binding momentum of $X$. We also derive an order-of-magnitude estimate of the $X$ cross section in terms of a naive charm-meson pair cross section that does not take into account the threshold enhancement, such as that produced by a Monte Carlo event generator. The cross section for producing $X$ can be approximated by the naive cross section for producing $D^{\ast 0}{\bar{D}}^0$ integrated up to a relative momentum $k_{\max }$ of order $(m_{\pi }^2{\gamma }_X{)}^{1/3}$. The estimates of the prompt $X$ cross section at hadron colliders are consistent with the cross sections observed at the Tevatron and the LHC.

   hep-phPRD(2019)·22 citations
8. 08*

   Complete One-Loop Matching for a Singlet Scalar in the Standard Model EFT

   Minyuan Jiang🇨🇳 · Nathaniel Craig🇺🇸 · Ying-Ying Li🇨🇳 · Dave Sutherland🇺🇸

   We present the results of the first complete one-loop matching calculation between the real singlet scalar extension of the Standard Model and the Standard Model effective field theory (SMEFT) at dimension six. Beyond their immediate relevance to the precision calculation of observables in singlet extensions of the Standard Model, our results illustrate a variety of general features of one-loop matching. We explore the interplay between non-supersymmetric non-renormalization theorems, the logarithmic dependence of Wilson coefficients, and the relevance of mixed diagrams in theories with large scale separation. In addition, we highlight some of the subtleties involved in computing observables at next-to-leading order in SMEFT by mapping our results to the $T$ parameter at one loop.

   hep-phJHEP(2019)·83 citations
9. 09*

   Collider signature of $V_2$ Leptoquark with $b\to s$ flavour observables

   Aritra Biswas🇮🇳 · Avirup Shaw🇮🇳 · Abhaya Kumar Swain🇮🇳

   The Leptoquark model has been instrumental in explaining the observed lepton flavour universality violating charged ($b\to c$) and neutral ($b\to s$) current anomalies that have been the cause for substantial excitement in particle physics recently. In this article we have studied the role of one (designated as $V_2^{\frac{4}{3}}$) of the components of {\boldmath$V_2$} Vector Leptoquark doublet with electromagnetic charge $\frac{4}{3}$ in explaining the neutral current ($b\to s$) anomalies $R_{K^{(\ast )}}$ and $B_s\to {\mu }^{+}{\mu }^{-}$. Moreover, we have performed a thorough collider search for this $V_2^{\frac{4}{3}}$ Leptoquark using $b\bar{b}{\ell }^{+}{\ell }^{-}$ ($\ell \equiv e,\mu$) final state at the Large Hadron Collider. From our collider analysis we maximally exclude the mass of the $V_2^{\frac{4}{3}}$ Leptoquark up to 2340 GeV at 95\% confidence level for the 13 TeV Large Hadron Collider for an integrated luminosity of 3000 ${\mathrm{fb}}^{-1}$. Furthermore, a significant portion of the allowed parameter space that is consistent with the neutral current ($b\to s$) observables is excluded by collider analysis.

   hep-phLHEP(2019)·19 citations
10. 10*

    $D^{\ast }$ polarization vs. $R_{D^{(\ast )}}$ anomalies in the leptoquark models

    Syuhei Iguro🇯🇵 · Teppei Kitahara🇩🇪 · Yuji Omura🇯🇵 · Ryoutaro Watanabe🇮🇹 · Kei Yamamoto🇨🇭

    Polarization measurements in $\bar{B}\to D^{(\ast )}\tau \overline{\nu }$ are useful to check consistency in new physics explanations for the $R_D$ and $R_{D^{\ast }}$ anomalies. In this paper, we investigate the $D^{\ast }$ and $\tau$ polarizations and focus on the new physics contributions to the fraction of a longitudinal $D^{\ast }$ polarization ($F_L^{D^{\ast }}$), which is recently measured by the Belle collaboration $F_L^{D^{\ast }}=0.60\pm 0.09$, in model-independent manner and in each single leptoquark model (${\mathrm{R}}_2$, ${\mathrm{S}}_1$ and ${\mathrm{U}}_1$) that can naturally explain the $R_{D^{(\ast )}}$ anomalies. It is found that $\mathcal{B}(B_c^{+}\to {\tau }^{+}\nu )$ severely restricts deviation from the Standard Model (SM) prediction of $F_{L,\text{SM}}^{D^{\ast }}=0.46\pm 0.04$ in the leptoquark models: [0.43, 0.44], [0.42, 0.48], and [0.43, 0.47] are predicted as a range of $F_L^{D^{\ast }}$ for the ${\mathrm{R}}_2$, ${\mathrm{S}}_1$, and ${\mathrm{U}}_1$ leptoquark models, respectively, where the current data of $R_{D^{(\ast )}}$ is satisfied at $1\sigma$ level. It is also shown that the $\tau$ polarization observables can much deviate from the SM predictions. The Belle II experiment, therefore, can check such correlations between $R_{D^{(\ast )}}$ and the polarization observables, and discriminate among the leptoquark models.

    hep-phhep-exJHEP(2019)·101 citations
11. 11*

    Stopping Quirks at the LHC

    Jared A. Evans🇺🇸 · Markus A. Luty🇺🇸

    Quirks are exotic particles charged under a new confining gauge group that can give rise to unique collider signatures, depending on their vector-like mass, quantum numbers, and the confinement scale. In this work, we consider the possibility that quirks produced at the LHC lose all of their kinetic energy through ionization loss before escaping the detector, and annihilate at a time when there are no active pp collisions. We recast an existing CMS search for out-of-time decays of R-hadrons to place new limits on quirk parameter space. We propose several simple modifications to the existing out-of-time search strategy that can give these searches sensitivity in regions of quirk parameter space not covered by any existing or proposed search strategy.

    hep-phhep-exJHEP(2019)·29 citations
12. 12*

    Infrared Effects of Ultraviolet Operators on Dark Matter Freeze-In

    Lindsay Forestell🇨🇦 · David E. Morrissey🇨🇦

    Dark matter (DM) that interacts too weakly with the Standard Model (SM) to reach full thermodynamic equilibrium can be still be created in significant amounts by rare SM collisions. This mechanism, called freeze-in, can proceed through a renormalizable connector operator with a very small coefficient, or a non-renormalizable connector operator suppressed by a large mass scale. In the latter non-renormalizable scenario, the dominant creation of DM particles typically occurs at the largest SM temperature attained during the radiation era (assuming a standard cosmological history), and for this reason it is referred to as ultraviolet freeze-in. We show that non-renormalizable operators can also contribute importantly to the DM density at lower temperatures down to below the mass of the DM particle. To do so, we compute the production, annihilation, and freeze-out of DM in a simple dark sector consisting of a massive Dirac fermion DM candidate coupled to a massless Abelian vector boson with the only connection to the SM through the fermionic Higgs portal operator. For a broad range of parameters in the theory, the dark sector is populated by ultraviolet freeze-in in the usual way, self-thermalizes to a dark temperature below that of the SM, and undergoes thermal freeze-out. We show that late residual freeze-in reactions during the freeze-out process can further populate the dark sector and increase the DM relic density beyond standard dark sector freeze-out.

    hep-ph12 citations
13. 13*

    QCD Improved Matching for Semi-Leptonic B Decays with Leptoquarks

    Jason Aebischer🇩🇪 · Andreas Crivellin🇨🇭 · Christoph Greub🇨🇭

    Leptoquarks (LQs) provide very promising solutions to the tensions between the experimental measurements and the SM predictions of $b\to s{\ell }^{+}{\ell }^{-}$ and $b\to c\tau \nu$ processes. In this case the LQ masses are in general at the TeV scale and they can thus be produced at high energy colliders and dedicated LHC searches are ongoing. While for LQ production and decay the $O({\alpha }_s)$ corrections have been known for a long time, the $O({\alpha }_s)$ corrections to the matching on 2-quark-2-lepton operators have not been calculated, yet. In this article we close this gap by computing the QCD corrections to the matching of LQ models on the effective SM Lagrangian for both scalar and vector LQs. We find an enhancement of the Wilson coefficients of vector operators with respect to the tree-level results of around 8 % (13 %) if they originate from scalar (vector) LQs. This softens the LHC bounds and increases the allowed parameter space of LQ models addressing the flavour anomalies.

    hep-phPRD(2019)·56 citations
14. 14*

    Can dark matter drive electroweak symmetry breaking?

    Catarina Cosme🇵🇹 · João G. Rosa🇵🇹 · Orfeu Bertolami🇵🇹

    We consider the possibility of an oscillating scalar field accounting for dark matter and dynamically controlling the spontaneous breaking of the electroweak symmetry through a Higgs-portal coupling. This requires a late decay of the inflaton field, such that thermal effects do not restore the electroweak symmetry after reheating, and so inflation is followed by an inflaton matter-dominated epoch. During inflation, the dark scalar field acquires a large expectation value due to a negative non-minimal coupling to curvature, thus stabilizing the Higgs field by holding it at the origin. After inflation, the dark scalar oscillates in a quartic potential, behaving as dark radiation, and only when its amplitude drops below a critical value does the Higgs field acquire a non-zero vacuum expectation value. The dark scalar then becomes massive and starts behaving as cold dark matter until the present day. We further show that consistent scenarios require dark scalar masses in the few GeV range, which may be probed with future collider experiments.

    hep-phastro-ph.COhep-thPRD(2020)·10 citations
15. 15*

    Model-independent femtoscopic Levy imaging for elastic proton-proton scattering

    T. Csorgo🇭🇺 · R. Pasechnik🇸🇪 · A. Ster🇭🇺

    A model independent Levy expansion method is introduced to describe nearly Levy shaped squared moduli of Fourier transforms. We apply this method to precisely characterize the most recent elastic scattering data of proton-proton collisions at $\sqrt{s}=13$ TeV. The results reveal a substructure of protons, which is found to be significantly larger and darker in high energy proton-proton collisions at the TeV scale, as compared to a rather faint and apparently overlooked sub-structure, that we also identify in elastic proton-proton scattering at the ISR energy range of $\sqrt{s}=23-62$ GeV.

    hep-phhep-exnucl-exnucl-th+1Phys.Part.Nucl.(2020)·8 citations
16. 16*

    Quasi-Renormalizable Quantum Field Theories

    Maxim V. Polyakov🇷🇺 · Kirill M. Semenov-Tian-Shansky🇷🇺 · Alexander O. Smirnov🇷🇺 · Alexey A. Vladimirov🇩🇪

    Leading logarithms (LLs) in massless non-renormalizable effective field theories (EFTs) can be computed with the help of non-linear recurrence relations. These recurrence relations follow from the fundamental requirements of unitarity, analyticity and crossing symmetry of scattering amplitudes and generalize the renormalization group technique for the case of non-renormalizable EFTs. We review the existing exact solutions of non-linear recurrence relations relevant for field theoretical applications. We introduce the new class of quantum field theories (quasi-renormalizable field theories) in which the resummation of LLs for $2\to 2$ scattering amplitudes gives rise to a possibly infinite number of the Landau poles.

    ↳ hep-thhep-phTheor.Math.Phys.(2019)·4 citations
17. 17*

    Basis light front quantization for the charged light mesons with color singlet Nambu--Jona-Lasinio interactions

    Shaoyang Jia🇺🇸 · James P. Vary🇺🇸

    We apply the basis light front quantization (BLFQ) approach to describe the valence structures of the charged light meson ground states. Specifically, the light front wavefunctions of ${\pi }^{\pm }$, ${\rho }^{\pm }$, $K^{\pm }$, and $K^{\ast \pm }$ are obtained as the eigenvectors of the light front effective Hamiltonians with confinement potentials supplemented by the color singlet Nambu--Jona-Lasinio (NJL) interactions. We adjust our model such that the spectrum of these ground states and the charge radii of the pseudoscalar states agree with experimental results. We present the elastic form factors and parton distribution amplitudes (PDAs) as illustrations of the internal structures of the pseudoscalar pions and kaons in terms of valence quarks.

    ↳ nucl-thhep-phPRC(2019)·98 citations
18. 18*

    Effect of Siegert's Theorem on Low-Energy Neutrino-Nucleus Interactions

    A.C. Hayes🇺🇸 · J.L. Friar🇺🇸

    We examine the importance of conserving the vector current in calculating low-energy neutrino-nucleus interactions by implicitly invoking Siegert's Theorem in describing the vector transverse electric current. We find that at low neutrino energies (E? <50 MeV), Siegert's Theorem can change neutrino cross sections for normal-parity non-spin-flip excitations by about a factor of two.The same is true of muon capture rates. At higher neutrino energies the effect of Siegert's Theorem diminishes, and by about 100 MeV the effect is very small.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2018)·2 citations
19. 19*

    The leading hadronic contribution to the running of the Weinberg angle using covariant coordinate-space methods

    Marco Cè🇩🇪 · Antoine Gérardin🇩🇪 · Konstantin Ottnad🇩🇪 · Harvey B. Meyer🇩🇪

    We present a preliminary study of the leading hadronic contribution to the running of the Weinberg angle ${\theta }_{\mathrm{W}}$. The running is extracted from the correlation function of the electromagnetic current with the vector part of the weak neutral current using both the standard time-momentum representation method and the Lorentz-covariant coordinate-space method recently introduced by Meyer. Both connected and disconnected contributions have been computed on $N_{\mathrm{f}}=2+1$ non-perturbatively $O(a)$-improved Wilson fermions configurations from the CLS initiative. Similar covariant coordinate-space methods can be used to compute the leading hadronic contribution to the anomalous magnetic moment of the muon $(g-2{)}_{\mu }$ and to the running of the QED coupling $\alpha$.

    ↳ hep-lathep-phPoS(2018)·20 citations
20. 20*

    Massless bosons on domain walls: Jackiw-Rebbi-like mechanism for bosonic fields

    Masato Arai🇯🇵 · Filip Blaschke🇨🇿 · Minoru Eto🇯🇵 · Norisuke Sakai🇯🇵

    It is important to obtain (nearly) massless localized modes for the low-energy four-dimensional effective field theory in the brane-world scenario. We propose a mechanism for bosonic zero modes using the field-dependent kinetic function in the classical field theory set-up. As a particularly simple case, we consider a domain wall in five dimensions, and show that massless states for scalar (0-form), vector (1-form), and tensor (2-form) fields appear on a domain wall, which may be called topological because of robustness of their existence (insensitive to continuous deformations of parameters). The spin of localized massless bosons is selected by the shape of the nonlinear kinetic function, analogously to the chirality selection of fermion by the well-known Jackiw-Rebbi mechanism. Several explicitly solvable examples are given. We consider not only (anti)BPS domain walls in non-compact extra dimension but also non-BPS domain walls in compact extra dimension.

    ↳ hep-thhep-phPRD(2019)·7 citations
21. 21*

    Statistical fluctuations of correlators in the Color Glass Condensate

    Francois Gelis🇫🇷 · Naoto Tanji🇮🇹

    In the McLerran-Venugopalan model, correlators of Wilson lines are given by an average over a Gaussian ensemble of random color sources. In numerical implementations, these averages are approximated by a Monte-Carlo sampling. In this paper, we study the statistical error made with such a sampling, with emphasis on the momentum dependence of this error. Using the example of the dipole amplitude, we consider various approximants that are all equivalent in the limit of infinite statistics but differ with finite statistics and compare their statistical errors. For correlation functions that are translation invariant, we show that averaging over the barycenter coordinate drastically reduces the statistical error and more importantly modifies its momentum dependence.

    ↳ nucl-thhep-ph1 citation
22. 22*

    Elementary charge and neutrino's mass from Planck length

    Saulo Carneiro🇧🇷

    It is shown that the postulation of a minimum length for the horizons of a black hole leads to lower bounds for the electric charges and magnetic moments of elementary particles. If the minimum length has the order of the Planck scale, these bounds are given, respectively, by the electronic charge and by $\mu \sim 10^{-21}{\mu }_B$. The latter implies that the masses of fundamental particles are bounded above by the Planck mass, and that the smallest non-zero neutrino mass is $m_{\nu }\sim 10^{-2}$eV. A precise estimation in agreement to the area quantisation of Loop Quantum Gravity predicts a mass for the lightest massive state in concordance with flavor oscillation measurements, and a Barbero-Immirzi parameter in accordance to horizon entropy estimations.

    ↳ gr-qchep-phhep-thFound.Phys.(2020)·8 citations
23. 23*

    Strongly intensive fluctuations and correlations in ultrarelativistic nuclear collisions in the model with string fusion

    Vladimir Kovalenko (Saint Petersburg State University)🇷🇺

    The several types of strongly intensive correlation variables are studied in nuclear collisions at LHC energy. These quantities are expected not to depend on centrality class width. They have been calculated in the dipole-based parton-string Monte Carlo model with string fusion. The centrality dependence of the mean transverse momentum correlation coefficient and strongly intensive quantity $\Sigma$ between multiplicity and $P_T$ have been obtained. Dynamical charge fluctuation ${\nu }_{dyn}$ has been also calculated and compared with experimental data. It is shown that string fusion improves agreement with the experiment.

    ↳ nucl-thhep-phEPJ Web Conf.(2019)·7 citations
24. 24*

    The distribution of dark matter in galaxies

    Paolo Salucci🇮🇹

    The distribution of the non-luminous matter in galaxies of different luminosity and Hubble type is much more than a proof of the existence of dark particles governing the structures of the Universe. Here, we will review the complex but well-ordered scenario of the properties of the dark halos also in relation with those of the baryonic components they host. Moreover, we will present a number of tight and unexpected correlations between selected properties of the dark and the luminous matter. Such entanglement evolves across the varying properties of the luminous component and it seems to unequivocally lead to a dark particle able to interact with the Standard Model particles over cosmological times. This review will also focus on whether we need a paradigm shift, from pure collisionless dark particles emerging from "first principles", to particles that we can discover only by looking to how they have designed the structure of the galaxies. \keywords{Dark matter \and Galaxies \and Cosmology \and Elementary particles}

    ↳ astro-ph.GAastro-ph.COgr-qchep-phAstron.Astrophys.Rev.(2019)·340 citations
25. 25*

    Further refining the de Sitter swampland conjecture

    David Andriot🇨🇭 · Christoph Roupec🇦🇹

    We propose an alternative refined de Sitter conjecture. It is given by a natural condition on a combination of the first and second derivatives of the scalar potential. We derive our conjecture in the same weak coupling, semi-classical regime where the previous refined de Sitter conjecture was derived, using the same tools together with a few more assumptions that we discuss. We further test and constrain free parameters in our conjecture using data points of a classical type IIA supergravity setup. Interestingly, our conjecture easily accommodates slow-roll single field inflation with a concave potential, favored by observations. The standard quintessence potential is in tension with our new conjecture, and we thus propose a different type of quintessence model.

    ↳ hep-thastro-ph.COgr-qchep-phFortsch.Phys.(2019)·160 citations
26. 26*

    All-optical signatures of quantum vacuum nonlinearities in generic laser fields

    Alexander Blinne🇩🇪 · Holger Gies🇩🇪 · Felix Karbstein🇩🇪 · Christian Kohlfürst🇩🇪 · Matt Zepf🇩🇪

    All-optical experiments at the high-intensity frontier offer a promising route to unprecedented precision tests of quantum electrodynamics in strong macroscopic electromagnetic fields. So far, most theoretical studies of all-optical signatures of quantum vacuum nonlinearity are based on simplifying approximations of the beam profiles and pulse shapes of the driving laser fields. Since precision tests require accurate quantitative theoretical predictions, we introduce an efficient numerical tool facilitating the quantitative theoretical study of all-optical signatures of quantum vacuum nonlinearity in generic laser fields. Our approach is based on the vacuum emission picture, and makes use of the fact that the dynamics of the driving laser fields are to an excellent approximation governed by classical Maxwell theory in vacuum. In combination with a Maxwell solver, which self-consistently propagates any given laser field configuration, this allows for accurate theoretical predictions of photonic signatures of vacuum nonlinearity in high-intensity laser experiments from first principles. We employ our method to simulate photonic signatures of quantum vacuum nonlinearity in laser pulse collisions involving a few-cycle pulse, and show that the angular and spectral distributions of the emitted signal photons deviate from those of the driving laser beams.

    ↳ physics.opticshep-phPRD(2019)·53 citations
27. 27*

    Testing diffusion of cosmic rays in the heliosphere with proton and helium data from AMS

    Nicola Tomassetti🇮🇹 · Fernando Barão🇵🇹 · Bruna Bertucci🇮🇹 · Emanuele Fiandrini🇮🇹 · José Figueiredo🇵🇹 · João Barreira🇵🇹 · Miguel Orcinha🇵🇹

    After six years of continuous observations in space, the Alpha Magnetic Spectrometer experiment has released new data on the temporal evolution of the proton and helium fluxes in cosmic rays. These data revealed that the ratio between proton and helium fluxes at the same value of rigidity $R=p/Z$ (momentum/charge ratio) is not constant at $R\lesssim$ 3 GV. In particular, the ratio is found to decrease steadily during the descending phase of Solar Cycle 24 toward the next minimum. We show that such a behavior is a remarkable signature of the $\beta \times \lambda (R)$ dependence in the diffusion of cosmic rays in heliosphere, where $\beta$ is their adimensional speed and $\lambda (R)$ is their mean free path, a universal function of rigidity for all nuclei. This dependence is responsible for distinctive charge/mass dependent effects in the time-dependent modulation of low-rigidity particles.

    ↳ astro-ph.HEastro-ph.SRhep-phphysics.space-phPRL(2018)·32 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.