Mon·Jul 3, 2017Monday·July 3, 2017

1. 01*

   Cold keV dark matter from decays and scatterings

   Julian Heeck🇧🇪 · Daniele Teresi🇧🇪

   We explore ways of creating cold keV-scale dark matter by means of decays and scatterings. The main observation is that certain thermal freeze-in processes can lead to a cold dark matter distribution in regions with small available phase space. In this way the free-streaming length of keV particles can be suppressed without decoupling them too much from the Standard Model. In all cases, dark matter needs to be produced together with a heavy particle that carries away most of the initial momentum. For decays, this simply requires an off-diagonal DM coupling to two heavy particles; for scatterings, the coupling of soft DM to two heavy particles needs to be diagonal, in particular in spin space. Decays can thus lead to cold light DM of any spin, while scatterings only work for bosons with specific couplings. We explore a number of simple models and also comment on the connection to the tentative 3.5 keV line.

   hep-phastro-ph.COPRD(2017)·109 citations
2. 02*

   Quasi Single Field Inflation in the non-perturbative regime

   Haipeng An🇺🇸 · Michael McAneny🇺🇸 · Alexander K. Ridgway🇺🇸 · Mark B. Wise🇺🇸

   In quasi single field inflation there are massive fields that interact with the inflaton field. If these other fields are not much heavier than the Hubble constant during inflation ($H$) these interactions can lead to important consequences for the cosmological energy density perturbations. The simplest model of this type has a real scalar inflaton field that interacts with another real scalar $S$ (with mass $m$). In this model there is a mixing term of the form $\mu \dot{\pi }S$, where $\pi$ is the Goldstone fluctuation that is associated with the breaking of time translation invariance by the time evolution of the inflaton field during the inflationary era. In this paper we study this model in the region $(\mu /H{)}^2+(m/H{)}^2>9/4$ and $m/H\sim \mathcal{O}(1)$ or less. For a large part of the parameter space in this region standard perturbative methods are not applicable. Using numerical and analytic methods we derive a number of new results. In addition we study how large $\mu /H$ has to be for the large $\mu /H$ effective field theory approach to be applicable.

   hep-phastro-ph.COhep-thJHEP(2018)·141 citations
3. 03*

   Supersymmetric Resonant Dark Matter: a Thermal Model for the AMS-02 Positron Excess

   Yang Bai🇺🇸 · Joshua Berger🇺🇸 · Sida Lu🇺🇸

   We construct a thermal dark matter model with annihilation mediated by a resonance to explain the positron excess observed by PAMELA, Fermi-LAT and AMS-02, while satisfying constraints from cosmic microwave background (CMB) measurements. The challenging requirement is that the resonance has twice the dark matter mass to one part in a million. We achieve this by introducing an $SU(3{)}_f$ dark flavor symmetry that is spontaneously broken to $SU(2{)}_f\times U(1{)}_f$. The resonance is the heaviest state in the dark matter flavor multiplet and the required mass relation is protected by the vacuum structure and supersymmetry from radiative corrections. The pseudo-Nambu Goldstone Bosons (PNGB's) from the dark flavor symmetry breaking can be slightly lighter than one GeV and dominantly decay into two muons just from kinematics, with subsequent decay into positrons. The PNGB's are produced in resonant dark matter semi-annihilation, where two dark matter particles annihilate into an anti-dark matter particle and a PNGB. The dark matter mass in our model is constrained to be below around 1.9 TeV from fitting thermal relic abundance, AMS-02 data and CMB constraints. The superpartners of Standard Model (SM) particles can cascade decay into a light PNGB along with SM particles, yielding a correlated signal of this model at colliders. One of the interesting signatures is a resonance of a SM Higgs boson plus two collimated muons, which has superb discovery potential at LHC Run 2.

   hep-phastro-ph.COastro-ph.HEhep-exPRD(2018)·35 citations
4. 04*

   NLO Rutherford Scattering and the Kinoshita-Lee-Nauenberg Theorem

   Abdullah Khalil🇿🇦

   We calculate to next-to-leading order accuracy the high-energy elastic scattering cross section for an electron off of a classical point source. We use the $\overline{\mathrm{MS}}$ renormalization scheme to tame the ultraviolet divergences while the infrared singularities are dealt with using the well known Kinoshita-Lee-Nauenberg theorem. We show for the first time how to correctly apply the Kinoshita-Lee-Nauenberg theorem diagrammatically in a next-to-leading order scattering process. We improve on previous works by including all initial and final state soft radiative processes, including absorption and an infinite sum of partially disconnected amplitudes. Crucially, we exploit the Monotone Convergence Theorem to prove that our delicate rearrangement of this formally divergent series is uniquely correct. This rearrangement yields a factorization of the infinite contribution from the initial state soft photons that then cancels in the physically observable cross section. Since we use the $\overline{\mathrm{MS}}$ renormalization scheme, our result is valid up to arbitrarily large momentum transfers between the source and the scattered electron as long as $\alpha \log (1/\delta )\ll 1$ and $\alpha \log (1/\delta )\log (\Delta /E)\ll 1$, where $\Delta$ and $\delta$ are the experimental energy and angular resolutions, respectively, and $E$ is the energy of the scattered electron. Our work aims at computing the NLO corrections to the energy loss of a high energetic parton propagating in a quark-gluon plasma.

   hep-phhep-th1 citation
5. 05*

   A Neutrinophilic 2HDM as a UV Completion for the Inverse Seesaw Mechanism

   Enrico Bertuzzo🇧🇷 · Pedro A. N. Machado🇺🇸 · Zahra Tabrizi🇧🇷 · Renata Zukanovich Funchal🇧🇷

   In Neutrinophilic Two Higgs Doublet Models, Dirac neutrino masses are obtained by forbidding a Majorana mass term for the right-handed neutrinos via a symmetry. We study a variation of such models in which that symmetry is taken to be a local U(1), leading naturally to the typical Lagrangian of the inverse seesaw scenario. The presence of a new gauge boson and of an extended scalar sector result in a rich phenomenology, including modifications to Z, Higgs and kaon decays as well as to electroweak precision parameters, and a pseudoscalar associated to the breaking of lepton number.

   hep-phJHEP(2017)·12 citations
6. 06*

   Heptaquarks with two heavy antiquarks in a simple chromomagnetic model

   Aaron Park🇰🇷 · Woosung Park🇰🇷 · Su Houng Lee🇰🇷

   We investigate the symmetry property and the stability of the heptaquark containing two identical heavy antiquarks using color-spin interaction. We construct the wave function of the heptaquark from the Pauli exclusion principle in the SU(3) breaking case. The stability of the heptaquark against the strong decay into one baryon and two mesons is discussed in a simple chromomagnetic model. We find that $q^2{s}^3{\bar{s}}^2$ with $I=0,S=\frac{5}{2}$ is the most stable heptaquark configuration that could be probed by reconstructing the $\Lambda +\varphi +\varphi$ invariant mass.

   hep-phPRD(2017)·6 citations
7. 07*

   Study of the rare decays $B_{s,d}^{\ast }\to {\mu }^{+}{\mu }^{-}$

   Suchismita Sahoo🇮🇳 · Rukmani Mohanta🇮🇳

   We study rare leptonic decays of vector $B$ mesons in the scalar leptoquark and family non-universal $Z^{\prime }$ models. We constrain these new couplings by using the measured branching fractions of $B_{s,d}\to {\mu }^{+}{\mu }^{-}$ processes and the existing $B_{s,d}^0-{\bar{B}}_{s,d}^0$ mixing data. We estimate the branching fractions of $B_{s,d}^{\ast }\to {\mu }^{+}{\mu }^{-}$ in both the models, which are found to be reasonably enhanced from their corresponding standard model values and within the reach of Run 2-3 of LHC.

   hep-phSpringer Proc.Phys.(2018)·0 citations
8. 08*

   Bottom-quark mass effects in associated production with $Z$ and $H$ bosons

   Davide Napoletano🇬🇧 · Frank Krauss🇬🇧 · Steffen Schumann🇩🇪

   In this study, predictions obtained in the four and in the five flavour schemes are compared for two important processes involving heavy flavours at the LHC: the production of a $Z$ or a Higgs boson in association with $b$ quarks. In particular we obtain predictions with \Sherpa's \MCatNLO implementation for the four--flavour scheme, treating the $b$'s as massive, and with multijet merging at leading and next-to leading order for the five--flavour scheme. While differences between the two schemes, at the inclusive level, are well understood from resummation of possibly large logs into the $b$-PDFs, differences in shape present a major problem for experimental measurements. We make use of data for $Z+b(\bar{b})$ production at the $7$ TeV LHC to exhibit strengths and weaknesses of the different approaches and we use these results to validate predictions for $b$-associated Higgs-boson production at the 13 TeV Run II.

   hep-phhep-exPoS(2018)·1 citation
9. 09*

   A new method to study the number of colors in the final-state interactions of hadrons

   Ling-Yun Dai🇩🇪 · Ulf-G. Meißner🇩🇪

   We match the $\pi \pi \to \pi \pi$ scattering amplitudes of Chiral Perturbation Theory with those from dispersion relations that respect analyticity and coupled channel unitarity, as well as accurately describing experiment. Their dependence on the number of colors ($N_C$) is obtained. By varying $N_C$ the trajectories of the poles and residues (the couplings to $\pi \pi$) of light mesons, the $\sigma$, $f_0(980)$, $\rho (770)$ and $f_2(1270)$ are investigated. Our results show that the method proposed is a reliable way to study the $N_C$ dependence in hadron-hadron scattering with final-state interactions.

   hep-phnucl-thPLB(2018)·16 citations
10. 10*

    Neutrino mass generation and leptogenesis via pseudo-Nambu-Goldstone Higgs portal

    Tommi Alanne🇩🇰 · Aurora Meroni🇫🇮 · Kimmo Tuominen🇫🇮

    We consider an extension of the Standard Model with the global symmetry breaking pattern SO(5)/SO(4), where the Higgs boson arises as a pseudo-Nambu-Goldstone boson. The scalar content of the theory consists of a Standard-Model-like Higgs field and an extra real scalar field. The flavour sector of the model is extended by two right-handed neutrinos compatible with the observed light-neutrino phenomenology, and we find that the correct vacuum alignment determines the mass of the heavier neutrino eigenstate to be around 80 TeV. The new singlet-scalar state generates dynamically a Majorana mass term for the heavy neutrino states. We show how the model leads to the correct baryon asymmetry of the universe via leptogenesis in the case of two degenerate or hierarchical heavy neutrinos.

    hep-phPRD(2017)·9 citations
11. 11*

    Bootstrapping the QCD soft anomalous dimension

    Øyvind Almelid🇬🇧 · Claude Duhr🇨🇭 · Einan Gardi🇬🇧 · Andrew McLeod🇺🇸 · Chris D. White🇬🇧

    The soft anomalous dimension governs the infrared singularities of scattering amplitudes to all orders in perturbative quantum field theory, and is a crucial ingredient in both formal and phenomenological applications of non-abelian gauge theories. It has recently been computed at three-loop order for massless partons by explicit evaluation of all relevant Feynman diagrams. In this paper, we show how the same result can be obtained, up to an overall numerical factor, using a bootstrap procedure. We first give a geometrical argument for the fact that the result can be expressed in terms of single-valued harmonic polylogarithms. We then use symmetry considerations as well as known properties of scattering amplitudes in collinear and high-energy (Regge) limits to constrain an ansatz of basis functions. This is a highly non-trivial cross-check of the result, and our methods pave the way for greatly simplified higher-order calculations.

    hep-phhep-thJHEP(2017)·127 citations
12. 12*

    Wigner Distributions of Quarks and Gluons

    Jai More🇮🇳 · Asmita Mukherjee🇮🇳 · Sreeraj Nair🇮🇳

    We present a recent calculation of Wigner distributions of quarks and gluons for a quark target state dressed with a gluon, using overlaps of light-front wave functions.

    hep-phPoS(2018)·1 citation
13. 13*

    Lepton-Jets and Low-Mass Sterile Neutrinos at Hadron Colliders

    Sourabh Dube🇮🇳 · Divya Gadkari🇮🇳 · Arun M. Thalapillil🇮🇳

    Sterile neutrinos, if they exist, are potential harbingers for physics beyond the Standard Model. They have the capacity to shed light on our flavor sector, grand unification frameworks, dark matter sector and origins of baryon anti-baryon asymmetry. There have been a few seminal studies that have broached the subject of sterile neutrinos with low, electroweak-scale masses (i.e. ${\Lambda }_{\text{QCD}}\ll m_{N_R}\ll m_{W^{\pm }}$) and investigated their reach at hadron colliders using lepton jets. These preliminary studies nevertheless assume background-free scenarios after certain selection criteria which are overly optimistic and untenable in realistic situations. These lead to incorrect projections. The unique signal topology and challenging hadronic environment also make this mass-scale regime ripe for a careful investigation. With the above motivations, we attempt to perform the first systematic study of low, electroweak-scale, right-handed neutrinos at hadron colliders, in this unique signal topology. There are currently no active searches at hadron colliders for sterile neutrino states in this mass range, and we frame the study in the context of the $13\mathrm{TeV}$ high-luminosity Large Hadron Collider and the proposed FCC-hh/SppC $100\mathrm{TeV}$ $pp$-collider.

    hep-phhep-exPRD(2017)·42 citations
14. 14*

    Triviality of quantum electrodynamics revisited

    D. Djukanovic🇩🇪 · J. Gegelia🇩🇪 · Ulf-G. Meißner🇩🇪

    Quantum electrodynamics is considered to be a trivial theory. This is based on a number of evidences, both numerical and analytical. One of the strong indications for triviality of QED is the existence of the Landau pole for the running coupling. We show that by treating QED as the leading order approximation of an effective field theory and including the next-to-leading order corrections, the Landau pole is removed. Therefore, we conclude that the conjecture, that for reasons of self-consistency, QED needs to be trivial is a mere artefact of the leading order approximation to the corresponding effective field theory.

    ↳ hep-thhep-lathep-phnucl-thCommun.Theor.Phys.(2018)·15 citations
15. 15*

    A lepto-hadronic model of gamma rays from the Eta Carinae and prospects for neutrino telescopes

    Nayantara Gupta🇮🇳 · Soebur Razzaque🇿🇦

    The stellar binary $\eta$ Carinae has been observed during its full orbital period in gamma rays by the Fermi-Large Area Telescope (LAT). The shock-accelerated electrons in the colliding winds of the two stars radiate synchrotron photons in the magnetic field of the shocked region and inverse Compton photons, where the target photons are from the thermal emissions by the more massive and luminous of the two stars. The inverse Compton emission dominates the gamma-ray flux data from the $\eta$ Carinae, however the spectral energy distribution shows signature of a hadronic component in the $\sim 10$-300 GeV range during the periastron passage. Current and future air Cherenkov telescopes will be able to constrain this component at TeV energies. Acceleration of cosmic-ray protons to $\gg 1$ TeV energies in the colliding winds, required to explain the hadronic emission component through photopion interactions, can lead to detectable signal of $\gtrsim 10$ TeV neutrino events in large kilometer scale neutrino telescopes.

    ↳ astro-ph.HEhep-exhep-phphysics.comp-phPRD(2017)·11 citations
16. 16*

    A search for low-energy neutrinos correlated with gravitational wave events GW150914, GW151226 and GW170104 with the Borexino detector

    M. Agostini🇮🇹 · K. Altenmuller🇩🇪 · S. Appel🇩🇪 · V. Atroshchenko🇷🇺 · Z. Bagdasarian🇩🇪 · D. Basilico🇮🇹 · G. Bellini🇮🇹 · J. Benziger🇺🇸 · D. Bick🇩🇪 · G. Bonfini🇮🇹 · D. Bravo🇺🇸 · B. Caccianiga🇮🇹 and 90 other authors

    We present the results of a low-energy neutrino search using the Borexino detector in coincidence with the gravitational wave (GW) events GW150914, GW151226 and GW170104. We searched for correlated neutrino events with energies greater than 250 keV within a time window of $\pm 500$ s centered around the GW detection time. A total of five candidates were found for all three GW150914, GW151226 and GW170104. This is consistent with the number of expected solar neutrino and background events. As a result, we have obtained the best current upper limits on the GW event neutrino fluence of all flavors (${\nu }_e,{\nu }_{\mu },{\nu }_{\tau }$) in the energy range $(0.5-5.0)$ MeV.

    ↳ astro-ph.HEhep-exhep-phApJ(2017)·30 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.