Fri·Sep 13, 2019Friday·September 13, 2019

1. 01*

   Cosmological Limits on the Neutrino Mass and Lifetime

   Zackaria Chacko🇺🇸 · Abhish Dev🇺🇸 · Peizhi Du🇺🇸 · Vivian Poulin🇫🇷 · Yuhsin Tsai🇺🇸

   At present, the strongest upper limit on $\sum m_{\nu }$, the sum of neutrino masses, is from cosmological measurements. However, this bound assumes that the neutrinos are stable on cosmological timescales, and is not valid if the neutrino lifetime is less than the age of the universe. In this paper, we explore the cosmological signals of theories in which the neutrinos decay into invisible dark radiation on timescales of order the age of the universe, and determine the bound on the sum of neutrino masses in this scenario. We focus on the case in which the neutrinos decay after becoming non-relativistic. We derive the Boltzmann equations that govern the cosmological evolution of density perturbations in the case of unstable neutrinos, and solve them numerically to determine the effects on the matter power spectrum and lensing of the cosmic microwave background. We find that the results admit a simple analytic understanding. We then use these results to perform a Monte Carlo analysis based on the current data to determine the limit on the sum of neutrino masses as a function of the neutrino lifetime. We show that in the case of decaying neutrinos, values of $\sum m_{\nu }$ as large as 0.9 eV are still allowed by the data. Our results have important implications for laboratory experiments that have been designed to detect neutrino masses, such as KATRIN and KamLAND-ZEN.

   hep-phastro-ph.HEJHEP(2020)·91 citations
2. 02*

   Probing Higgs couplings to light quarks via Higgs pair production

   Lina Alasfar🇩🇪 · Roberto Corral Lopez🇪🇸 · Ramona Gröber🇩🇪

   We consider the potential of the Higgs boson pair production process to probe the light quark Yukawa couplings. We show within an effective theory description that the prospects of constraining enhanced first generation light quark Yukawa couplings in Higgs pair production are similar to other methods and channels, due to a coupling of two Higgs bosons to two fermions. Higgs pair production can hence also probe if the Higgs sector couples non-linearly to the light quark generations. For the second generation, we show that by employing charm tagging for the Higgs boson pair decaying to $c\bar{c}\gamma \gamma$, we can obtain similarly good prospects for measuring the charm Yukawa coupling as in other direct probes.

   hep-phhep-exJHEP(2019)·43 citations
3. 03*

   DAMA/LIBRA annual modulation and Axion Quark Nugget Dark Matter Model

   Ariel Zhitnitsky🇨🇦

   The DAMA/LIBRA experiment shows $9.5\sigma$ evidence for an annual modulation in the $(1-6)\mathrm{keV}$ energy range, strongly suggesting that the observed modulation has the dark matter origin. However, the conventional interpretation in terms of WIMP-nucleon interaction is excluded by other experiments. We propose an alternative source of modulation in the form of neutrons, which have been liberated from surrounding material. Our computations are based on the so-called Axion Quark Nugget (AQN) dark matter model, which was originally invented long ago to explain the similarity between the dark and visible cosmological matter densities, i.e. ${\Omega }_{\mathrm{dark}}\sim {\Omega }_{\mathrm{visible}}$. In our proposal the annual modulation is shown to be generated in keV energy range which is consistent with DL observation in $(1-6)\mathrm{keV}$ range. This keV energy scale in our proposal is mostly determined by spectral properties of the neutrinos emitted by the AQN dark matter particles, while the absence of the modulation with energies above 6 keV is explained by a sharp cutoff in the neutrino's energy spectrum at $\sim 15$ MeV. This proposal can be directly tested by COSINE-100, ANAIS-112, CYGNO and other similar experiments. It can be also tested by studying the correlations between the signals from these experiments and the signatures from drastically different detectors designed for studies of the infrasonic or seismic events using such instruments as Distributed Acoustic Sensing (DAS).

   hep-phastro-ph.COhep-exPRD(2020)·18 citations
4. 04*

   Chiral Froggatt-Nielsen models, gauge anomalies and flavourful axions

   Q. Bonnefoy🇩🇪 · E. Dudas🇫🇷 · S. Pokorski🇵🇱

   We study UV-complete Froggatt-Nielsen-like models for the generation of mass and mixing hierarchies, assuming that the integrated heavy fields are chiral with respect to an abelian Froggatt-Nielsen symmetry. It modifies the mixed anomalies with respect to the Standard Model gauge group, which opens up the possibility to gauge the Froggatt-Nielsen symmetry without the need to introduce additional spectator fermions, while keeping mass matrices usually associated to anomalous flavour symmetries. We give specific examples where this happens, and we study the flavourful axion which arises from an accidental Peccei-Quinn symmetry in some of those models. Such an axion is typically more coupled to matter than in models with spectator fermions.

   hep-phhep-thJHEP(2020)·43 citations
5. 05*

   Constraining nuclear Parton Density Functions with forward photon production at the LHC

   Marco van Leeuwen🇳🇱

   In this paper we explore the use of results on forward particle production at the LHC to constrain nuclear Parton Density Functions (nPDFs). The case study here is based on a possible future measurement of forward photon production with the Forward Calorimeter that is currently under discussion as an upgrade of the ALICE experiment. As a starting point, we use the recent nNNPDF 1.0 nuclear PDFs, which have been determined using fixed target neutral-current DIS data, which constrain the gluon density at x > $10^{-2}$. The Bayesian reweighting technique is used to include the constraints from the future measurement.

   hep-ph11 citations
6. 06*

   Probe Of Sterile Neutrinos Using Astrophysical Neutrino Flavor

   Carlos A. Argüelles🇺🇸 · Kareem Farrag🇬🇧 · Teppei Katori🇬🇧 · Rishabh Khandelwal🇺🇸 · Shivesh Mandalia🇬🇧 · Jordi Salvado🇪🇸

   In this paper, we study the effect of active-neutrino-sterile-neutrino mixing in the expected high-energy astrophysical neutrino flavor content. Non-unitarity in the measurement of the three active neutrinos can be due to the existence of sterile neutrino states. We introduce the concept of the four-flavor tetrahedron in order to visualize the lack of unitarity in the astrophysical neutrino three-flavor triangle. We demonstrate that active-sterile neutrino mixings modify the allowed region of the astrophysical flavor ratio from the standard case. However, a projection of the four-flavor tetrahedron has restrictions of phase space similar to the three-flavor triangle. On the other hand, the initial presence of astrophysical sterile neutrinos drastically changes the scenario, and it allows an apparent unitarity violation in the three-flavor triangle space. Using current global fit constraints including the non-unitarity case, we also illustrate the allowed astrophysical neutrino flavor ratios. Thus, the measurement of the high-energy astrophyscal neutrino flavor content allows us to explore sterile neutrinos independently of the sterile neutrino mass scale. These are topics of investigation for current and future neutrino telescopes.

   hep-phJCAP(2020)·34 citations
7. 07*

   Empirical inference on the Majorana mass of the ordinary neutrinos

   Stefano Dell'Oro🇺🇸 · Simone Marcocci🇺🇸 · Francesco Vissani🇮🇹

   There is a broad theoretical consensus on the idea that ordinary neutrinos have a Majorana mass, but we have no clear prediction about its value, and direct experimental measurements of this quantity are rather challenging. In this work, we argue that the current cosmological measurements allow us to obtain precise information on the effective Majorana mass, i.e. the electronic-type mass of ordinary neutrinos. We show that the numerical results that we obtain can be accurately reproduced, and hence tested, by a straightforward analytical procedure. We then discuss the stability of the assumptions at the basis of our analysis and the implications of our findings for neutrinoless double beta decay.

   hep-phPRD(2019)·9 citations
8. 08*

   Probing the anomalous triple gauge boson couplings in $e^{+}{e}^{-}\to W^{+}{W}^{-}$ using $W$ polarizations with polarized beams

   Rafiqul Rahaman🇮🇳 · Ritesh K. Singh🇮🇳

   We study the anomalous $W^{+}{W}^{-}V$ ($V=\gamma ,Z$) couplings in $e^{+}{e}^{-}\to W^{+}{W}^{-}$ using the complete set of polarization observables of $W$ boson with longitudinally polarized electron ($e^{-}$) and positron ($e^{+}$) beams. For the effective $W^{+}{W}^{-}V$ couplings, we use the most general Lorentz invariant form factor parametrization as well as $SU(2)\times U(1)$ invariant dimension-$6$ effective operators. We estimate simultaneous limits on the anomalous couplings using the Markov-Chain--Monte-Carlo (MCMC) method for an $e^{+}{e}^{-}$ collider running at center of mass energy of $\sqrt{s}=500$ GeV and the integrated luminosity of $\mathcal{L}=100$ fb${}^{-1}$, $3.2$ ab${}^{-1}$ and $4$ ab${}^{-1}$. The best limits on the anomalous couplings are obtained for $e^{-}$ and $e^{+}$ polarization being $(\pm 0.8,\mp 0.6)$ for both $100$ fb${}^{-1}$ and $3.2$ ab${}^{-1}$ of luminosity.

   hep-phhep-exPRD(2020)·18 citations
9. 09*

   CP asymmetry in $\tau \to K_S\pi {\nu }_{\tau }$ decays within the Standard Model and beyond

   Feng-Zhi Chen🇨🇳 · Xin-Qiang Li🇨🇳 · Ya-Dong Yang🇨🇳 · Xin Zhang🇨🇳

   Motivated by the $2.8\sigma$ discrepancy observed between the BaBar measurement and the Standard Model prediction of the CP asymmetry in $\tau \to K_S\pi {\nu }_{\tau }$ decays, as well as the prospects of future measurements at Belle II, we revisit this observable in this paper. Firstly, we reproduce the known CP asymmetry due to $K^0-{\bar{K}}^0$ mixing by means of the reciprocal basis, which is convenient when a $K_{S(L)}$ is involved in the final state. As the $K\pi$ tensor form factor plays a crucial role in generating a non-zero direct CP asymmetry that can arise only from the interference of vector and tensor operators, we then present a dispersive representation of this form factor, with its phase obtained in the context of chiral theory with resonances, which fulfills the requirements of unitarity and analyticity. Finally, the $\tau \to K_S\pi {\nu }_{\tau }$ decays are analyzed both within a model-independent low-energy effective theory framework and in a scalar leptoquark scenario. It is observed that the CP anomaly can be accommodated in the model-independent framework, even at the $1\sigma$ level, together with the constraint from the branching ratio of ${\tau }^{-}\to K_S{\pi }^{-}{\nu }_{\tau }$ decay; it can be, however, marginally reconciled only at the $2\sigma$ level, due to the specific relation between the scalar and tensor operators in the scalar leptoquark scenario. Once the combined constraints from the branching ratio and the decay spectrum of this decay are taken into account, these possibilities are however both excluded, even without exploiting further the stronger bounds from the (semi-)leptonic kaon decays under the assumption of lepton-flavour universality, as well as from the neutron electric dipole moment and $D-\bar{D}$ mixing under the assumption of $SU(2)$ invariance of the weak interactions.

   hep-phhep-exPRD(2019)·37 citations
10. 10*

    Classification of anomaly-free 2HDMs with a gauged U(1)' symmetry

    Astrid Ordell🇸🇪 · Roman Pasechnik🇸🇪 · Hugo Serôdio🇸🇪 · Franz Teichmann

    Two-Higgs-doublet models (2HDMs) with a flavored U(1)' gauge symmetry are a popular extension to the Standard Model (SM), yet they currently lack a complete survey. In this paper, we present a full classification of anomaly-free 2HDMs within the SM fermion content, resulting in a total of eleven distinct models. Four of these are relatively well-studied, while the rest either partially, or entirely, lack previous treatment. We study these textures under a variety of experimental bounds, focusing mainly on the previously unexplored models. This work is intended to act as a catalog to models worth considering in greater detail.

    hep-phPRD(2019)·17 citations
11. 11*

    On the Importance of NNLO QCD and Isospin-breaking Corrections in ${\epsilon }^{\prime }/\epsilon$

    Jason Aebischer🇩🇪 · Christoph Bobeth🇩🇪 · Andrzej J. Buras🇩🇪

    Following the 1999 analysis of Gambino, Haisch and one of us, we stress that all the recent NLO analyses of ${\epsilon }^{\prime }/\epsilon$ in the Standard Model (SM) suffer from the renormalization scheme dependence present in the electroweak penguin contributions as well as from scale uncertainties in them related to the matching scale ${\mu }_W$ and in particular to ${\mu }_t$ in $m_t({\mu }_t)$. We also reemphasize the important role of isospin-breaking and QED effects in the evaluation of ${\epsilon }^{\prime }/\epsilon$. Omitting all these effects, as done in the 2015 analysis by RBC-UKQCD collaboration, and choosing as an example the QCD penguin ($Q_6$) and electroweak penguin ($Q_8$) parameters $B_6^{(1/2)}$ and $B_8^{(3/2)}$ to be $B_6^{(1/2)}=0.80\pm 0.08$ and $B_8^{(3/2)}=0.76\pm 0.04$ at $\mu =m_c=1.3$ GeV, we find $({\epsilon }^{\prime }/\epsilon {)}_{\text{SM}}=(9.4\pm 3.5)\times 10^{-4}$, whereas including them results in $({\epsilon }^{\prime }/\epsilon {)}_{\text{SM}}=(5.6\pm 2.4)\times 10^{-4}$. This is an example of an anomaly at the $3.3\sigma$ level, which would be missed without these corrections. NNLO QCD contributions to QCD penguins are expected to further enhance this anomaly. We provide a table for ${\epsilon }^{\prime }/\epsilon$ for different values of $B_6^{(1/2)}$ and the isospin-breaking parameter ${\hat{\Omega }}_{\text{eff}}$, that should facilitate monitoring the values of ${\epsilon }^{\prime }/\epsilon$ in the SM when the RBC-UKQCD calculations of hadronic matrix elements including isospin-breaking corrections and QED effects will improve with time.

    hep-phhep-exhep-latEPJC(2020)·586 citations
12. 12*

    Electroweakino and slepton pair production at the LHC in NLO+NLL with resummation-improved PDFs

    J. Fiaschi🇩🇪 · M. Klasen🇩🇪

    Using parton density functions (PDFs) with threshold-resummation improvement, we consistently calculate higgsino/gaugino and slepton pair production at next-to-leading order and next-to-leading logarithmic accuracy at the LHC. The smaller PDF uncertainty of the global PDF sets is exploited with a factorisation method, which also avoids complications arising in the refitting of threshold-resummation improved PDF replicas in Mellin space. We explicitly take into account the reduction of the scale uncertainty due to the resummation. We show that the resummation contributions in the PDF fits partially compensate the cross section enhancements induced by those in the partonic matrix elements.

    hep-phPoS(2020)·1 citation
13. 13*

    Molecular states from ${\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}-{\Lambda }_c{\bar{D}}^{(\ast )}$ interaction

    Jun He🇨🇳 · Dian-Yong Chen🇨🇳

    In this work, we systemically investigate the molecular states from the ${\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}-{\Lambda }_c{\bar{D}}^{(\ast )}$ interaction with the help of the Lagrangians with heavy quark and chiral symmetries in a quasipotential Bethe-Salpeter equation (qBSE) approach. The molecular states are produced from isodoublet (I=1/2) ${\Sigma }_c\bar{D}$ interaction with spin parity $J^P=1/2^{-}$ and ${\Sigma }_c{\bar{D}}^{\ast }$ interaction with $1/2^{-}$ and $3/2^{-}$. Their masses and widths are consistent with the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ observed at LHCb. The states, ${\Sigma }_c^{\ast }{\bar{D}}^{\ast }(1/2^{-})$, ${\Sigma }_c^{\ast }{\bar{D}}^{\ast }(3/2^{-})$ and ${\Sigma }_c^{\ast }\bar{D}(3/2^{-})$, are also produced with the same parameters. The isodoublet ${\Sigma }_c^{\ast }{\bar{D}}^{\ast }$ interaction with $5/2^{-}$, as well as the isoquartet (I=3/2) ${\Sigma }_c{\bar{D}}^{\ast }$ interactions with $1/2^{-}$ and $3/2^{-}$, ${\Sigma }_c^{\ast }{\bar{D}}^{\ast }$ interaction with $3/2^{-}$ and $5/2^{-}$, are also attractive while very large cutoff is required to produce a molecular state. We also investigate the origin of the widths of these molecular states in the same qBSE frame. The $\Lambda {\bar{D}}^{\ast }$ channel is dominant in the decays of the states, ${\Sigma }_c{\bar{D}}^{\ast }(1/2^{-})$, ${\Sigma }_c{\bar{D}}^{\ast }(3/2^{-})$, ${\Sigma }_c^{\ast }\bar{D}(3/2^{-})$, and ${\Sigma }_c\bar{D}(1/2^{-})$. The ${\Sigma }_c^{\ast }{\bar{D}}^{\ast }(1/2^{-})$ state has large coupling to ${\Sigma }_c\bar{D}$ channel while the ${\Sigma }_c{\bar{D}}^{\ast }$, ${\Sigma }_c^{\ast }\bar{D}$ and ${\Lambda }_c{\bar{D}}^{\ast }$ channels provide similar contributions to the width of the ${\Sigma }_c^{\ast }{\bar{D}}^{\ast }(3/2^{-})$ state. These results will be helpful to understand the current LHCb experimental results, and the three predicted states and the decay pattern of these hidden-charmed molecular pentaquarks can be checked in future experiments.

    hep-phEPJC(2019)·73 citations
14. 14*

    2-loop RG evolution of CP-violating 2HDM

    Joel Oredsson🇸🇪 · Johan Rathsman🇸🇪

    We use the recently developed code 2HDME to perform a 2-loop renormalization group analyzis of the CP violating Two-Higgs-doublet model (2HDM). Using parameter scans of several scenarios of Z2 symmetry breaking, we investigate the properties of 2HDMs under renormalization group evolution. Collider data constraints are implemented with HiggsBounds and HiggsSignals and we include all the important Barr-Zee diagram contributions to the electron's electric dipole moment to put limits on the CP violation that is allowed both in the scalar and the Yukawa sector. As a result, we see that the CP violation spreads easily across the sectors during renormalization group evolution when one breaks the Z2 symmetry in either sector, putting additional constraints on the CP violating parameters.

    hep-ph8 citations
15. 15*

    Studies of gluon TMDs and their evolution using quarkonium-pair production at the LHC

    Florent Scarpa🇳🇱 · Daniël Boer🇳🇱 · Miguel G. Echevarria🇮🇹 · Jean-Philippe Lansberg🇫🇷 · Cristian Pisano🇮🇹 · Marc Schlegel🇺🇸

    $J/\psi$- or ${\rm Y}$-pair production at the LHC are promising processes to study the gluon transverse momentum distributions (TMDs) which remain very poorly known. In this article, we improve on previous results by including the TMD evolution in the computation of the observables such as the pair-transverse-momentum spectrum and asymmetries arising from the linear polarization of gluons inside unpolarized protons. We show that the azimuthal asymmetries generated by the gluon polarization are reduced compared to the tree level case but are still of measurable size (in the 5%-10% range). Such asymmetries should be measurable in the available data sets of $J/\psi$ pairs and in the future data sets of the high-luminosity LHC for ${\rm Y}$ pairs.

    hep-phhep-exEPJC(2020)·79 citations
16. 16*

    Role of event multiplicity on hadronic phase lifetime and QCD phase boundary in ultrarelativistic collisions at energies available at the BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider

    Dushmanta Sahu🇮🇳 · Sushanta Tripathy🇮🇳 · Girija Sankar Pradhan🇮🇳 · Raghunath Sahoo🇮🇳

    Hadronic resonances, having very short lifetime, like ${\mathrm{K}}^{\ast 0}$, can act as useful probes to understand and estimate lifetime of hadronic phase in ultra-relativistic proton-proton, p--Pb and heavy-ion collisions. Resonances with relatively longer lifetime, like $\varphi$ meson, can serve as a tool to locate the QGP phase boundary. We estimate a lower limit of hadronic phase lifetime in Cu--Cu and Au--Au collisions at RHIC, and in pp, p--Pb and Pb--Pb collisions at different LHC collision energies. Also, we obtain the effective temperature of $\varphi$ meson using Boltzmann-Gibbs Blast-Wave function, which gives an insight to locate the QGP phase boundary. We observe that the hadronic phase lifetime strongly depends on final state charged-particle multiplicity, whereas the QGP phase and hence the QCD phase boundary shows a very weak multiplicity dependence. This suggests that the hadronisation from a QGP state starts at a similar temperature irrespective of charged-particle multiplicity, collision system and collision energy, while the endurance of hadronic phase is strongly dependent on final state charge-particle multiplicity, system size and collision energy.

    hep-phhep-exnucl-exnucl-thPRC(2020)·29 citations
17. 17*

    Baryon Number, Lepton Number, and Operator Dimension in the SMEFT with Flavor Symmetries

    Andreas Helset🇩🇰 · Andrew Kobach🇺🇸

    For a large set of flavor symmetries, the lowest-dimensional baryon- or lepton-number violating operators in the Standard Model effective field theory (SMEFT) with flavor symmetry are of mass dimension 9. As a consequence, baryon- and lepton-number violating processes are further suppressed with the introduction of flavor symmetries, e.g., the allowed scale associated with proton decay is typically lowered to $10^5$ GeV, which is significantly lower than the GUT scale. To illustrate these features, we discuss Minimal Flavor Violation for the Standard Model augmented by sterile neutrinos.

    hep-phPLB(2020)·45 citations
18. 18*

    FeynMaster: a plethora of Feynman tools

    Duarte Fontes🇵🇹 · Jorge C. Romão🇵🇹

    FeynMaster is a multi-tasking software for particle physics studies. By making use of already existing programs (FeynRules, QGRAF, FeynCalc), FeynMaster automatically generates Feynman rules, generates and draws Feynman diagrams, generates amplitudes, performs both loop and algebraic calculations, and fully renormalizes models. In parallel with this automatic character, FeynMaster allows the user to manipulate the generated results in Mathematica notebooks in a flexible and consistent way. It can be downloaded in https://porthos.tecnico.ulisboa.pt/FeynMaster/.

    hep-phComput.Phys.Commun.(2020)·27 citations
19. 19*

    Transport coefficients of hot and dense hadron gas in a magnetic field: a relaxation time approach

    Arpan Das🇮🇳 · Hiranmaya Mishra🇮🇳 · Ranjita K. Mohapatra🇮🇳

    We estimate various transport coefficients of hot and dense hadronic matter in the presence of magnetic field. The estimation is done through solutions of the relativistic Boltzmann transport equation in the relaxation time approximation.We have investigated the temperature and the baryon chemical potential dependence of these transport coefficients. Explicit calculations are done for the hadronic matter in the ambit of hadron resonance gas model. We estimate thermal conductivity, electrical conductivity and the shear viscosity of hadronic matter in the presence of a uniform magnetic field. Magnetic field, in general, makes the transport coefficients anisotropic. It is also observed that all the transport coefficients perpendicular to the magnetic field are smaller compared to their isotropic counterpart.

    hep-phnucl-thPRD(2019)·58 citations
20. 20*

    Cosmological Parameters from the BOSS Galaxy Power Spectrum

    Mikhail M. Ivanov🇺🇸 · Marko Simonović🇨🇭 · Matias Zaldarriaga🇺🇸

    We present cosmological parameter measurements from the publicly available Baryon Oscillation Spectroscopic Survey (BOSS) data on anisotropic galaxy clustering in Fourier space. Compared to previous studies, our analysis has two main novel features. First, we use a complete perturbation theory model that properly takes into account the non-linear effects of dark matter clustering, short-scale physics, galaxy bias, redshift-space distortions, and large-scale bulk flows. Second, we employ a Markov-Chain Monte-Carlo technique and consistently reevaluate the full power spectrum likelihood as we scan over different cosmologies. Our baseline analysis assumes minimal $\Lambda$CDM, varies the neutrino masses within a reasonably tight range, fixes the primordial power spectrum tilt, and uses the big bang nucleosynthesis prior on the physical baryon density ${\omega }_b$. In this setup, we find the following late-Universe parameters: Hubble constant $H_0=(67.9\pm 1.1)$ kms${}^{-1}$Mpc${}^{-1}$, matter density fraction ${\Omega }_m=0.295\pm 0.010$, and the mass fluctuation amplitude ${\sigma }_8=0.721\pm 0.043$. These parameters were measured directly from the BOSS data and independently of the Planck cosmic microwave background observations. Scanning over the power spectrum tilt or relaxing the other priors do not significantly alter our main conclusions. Finally, we discuss the information content of the BOSS power spectrum and show that it is dominated by the location of the baryon acoustic oscillations and the power spectrum shape. We argue that the contribution of the Alcock-Paczynski effect is marginal in $\Lambda$CDM, but becomes important for non-minimal cosmological models.

    ↳ astro-ph.COgr-qchep-phJCAP(2020)·556 citations
21. 21*

    Infrared renormalon in $SU(N)$ QCD(adj.) on ${\mathbb{R}}^3\times S^1$

    Masahiro Ashie🇯🇵 · Okuto Morikawa🇯🇵 · Hiroshi Suzuki🇯🇵 · Hiromasa Takaura🇯🇵 · Kengo Takeuchi🇯🇵

    We study the infrared renormalon in the gluon condensate in the $SU(N)$ gauge theory with $n_W$-flavor adjoint Weyl fermions (QCD(adj.)) on~${\mathbb{R}}^3\times S^1$ with the ${\mathbb{Z}}_N$ twisted boundary conditions. We rely on the so-called large-${\beta }_0$ approximation as a conventional tool to analyze the renormalon, in which only Feynman diagrams that dominate in the large-$n_W$ limit are considered while the coefficient of the vacuum polarization is set by hand to the one-loop beta function~${\beta }_0=11/3-2n_W/3$. In the large~$N$ limit within the large-${\beta }_0$ approximation, the W-boson, which acquires the twisted Kaluza--Klein momentum, produces the renormalon ambiguity corresponding to the Borel singularity at~$u=2$. This provides an example that the system in the compactified space~${\mathbb{R}}^3\times S^1$ possesses the renormalon ambiguity identical to that in the uncompactified space~${\mathbb{R}}^4$. We also discuss the subtle issue that the location of the Borel singularity can change depending on the order of two necessary operations.

    ↳ hep-thhep-lathep-phPTEP(2020)·9 citations
22. 22*

    Axion boson stars

    Davide Guerra🇮🇹 · Caio F. B. Macedo🇧🇷 · Paolo Pani🇮🇹

    We study novel solitonic solutions to Einstein-Klein-Gordon theory in the presence of a periodic scalar potential arising in models of axion-like particles. The potential depends on two parameters: the mass of the scalar field $m_a$ and the decay constant $f_a$; the standard case of the QCD axion is recovered when $m_a\propto 1/f_a$. When $f_a\to \infty$ the solutions reduce to the standard case of "mini" boson stars supported by a massive free scalar field. As the energy scale $f_a$ of the scalar self-interactions decreases we unveil several novel features of the solution: new stability branches emerge at high density, giving rise to very compact, radially stable, boson stars. Some of the most compact configurations acquire a photon sphere. When $f_a$ is at the GUT scale, a boson star made of QCD axions can have a mass up to ten solar masses and would be more compact than a neutron star. Gravitational-wave searches for these exotic compact objects might provide indirect evidence for ultralight axion-like particles in a region not excluded by the black-hole superradiant instability.

    ↳ gr-qcastro-ph.HEhep-phJCAP(2019)·96 citations
23. 23*

    Inflation, Dark Energy and Dark Matter in Supergravity

    Sergei V. Ketov🇯🇵

    The Dark Side of the Universe, which includes the cosmological inflation in the early Universe, the current dark energy and dark matter, can be theoretically described by supergravity, though it is non-trivial. We recall the arguments pro and contra supersymmetry and supergravity, and define the viable supergravity models describing the Dark Side of the Universe in agreement with all current observations. Our approach to inflation is based on the Starobinsky model, the dark energy is identified with the positive cosmological constant (de Sitter vacuum), and the dark matter particle is given by the lightest supersymmetric particle identified with the supermassive gravitino. The key role is played by spontaneous supersymmetry breaking.

    ↳ hep-thgr-qchep-ph4 citations
24. 24*

    Pseudoscalar glueball mass: a window on three-gluon interactions

    E. V. Souza🇧🇷 · M. N. Ferreira🇧🇷 · A. C. Aguilar🇧🇷 · J. Papavassiliou🇪🇸 · C. D. Roberts🇨🇳 · S.-S. Xu🇨🇳

    In pure-glue QCD, gluon-gluon scattering in the $J^{PC}=0^{-+}$ channel is described by a very simple equation, especially if one considers just the leading contribution to the scattering kernel. Of all components in this kernel, only the three-gluon vertex, $V_{\mu \nu \rho }$, is poorly constrained by contemporary analyses; hence, calculations of $0^{-+}$ glueball properties serve as a clear window onto the character and form of $V_{\mu \nu \rho }$. This is important given that many modern calculations of $V_{\mu \nu \rho }$ predict the appearance of an infrared suppression in the scalar function which comes to modulate the bare vertex after the nonperturbative resummation of interactions. Such behaviour is a peculiar prediction; but we find that such suppression is essential if one is to achieve agreement with lattice-QCD predictions for the $0^{-+}$ glueball mass. It is likely, therefore, that this novel feature of $V_{\mu \nu \rho }$ is real and has observable implications for the spectrum, decays and interactions of all QCD bound-states.

    ↳ nucl-thhep-lathep-phnucl-exEPJA(2020)·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.