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Title: Muon g−2 and Galactic Centre γ-ray excess in a scalar extension of the 2HDM type-X

Abstract

We consider an extension of the lepto-specific 2HDM with an extra singlet S as a dark matter candidate. Taking into account theoretical and experimental constraints, we investigate the possibility to address both the γ-ray excess detected at the Galactic Centre and the discrepancy between the Standard Model prediction and experimental results of the anomalous magnetic moment of the muon. Our analyses reveal that the SS→τ{sup +}τ{sup −} and SS→bb-bar channels reproduce the Galactic Centre excess, with an emerging dark matter candidate which complies with the bounds from direct detection experiments, measurements of the Higgs boson invisible decay width and observations of the dark matter relic abundance. Addressing the anomalous magnetic moment of the muon imposes further strong constraints on the model. Remarkably, under these conditions, the SS→bb-bar channel still allows for the fitting of the Galactic Centre. We also comment on a scenario allowed by the model where the SS→τ{sup +}τ{sup −} and SS→bb-bar channels have comparable branching ratios, which possibly yield an improved fitting of the Galactic Centre excess.

Authors:
;  [1];  [1];  [2]
  1. National Institute of Chemical Physics and Biophysics,Rävala pst. 10, Tallinn, 10143 (Estonia)
  2. (Estonia)
Publication Date:
Sponsoring Org.:
SCOAP3, CERN, Geneva (Switzerland)
OSTI Identifier:
22458393
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 10; Other Information: PUBLISHER-ID: JCAP10(2015)025; OAI: oai:repo.scoap3.org:12241; Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ABUNDANCE; BRANCHING RATIO; DETECTION; GALAXIES; GAMMA RADIATION; HIGGS BOSONS; MAGNETIC MOMENTS; NONLUMINOUS MATTER; RELICT RADIATION; STANDARD MODEL

Citation Formats

Hektor, Andi, Kannike, Kristjan, Marzola, Luca, and Institute of Physics, University of Tartu,Ravila 14c, Tartu, 50411. Muon g−2 and Galactic Centre γ-ray excess in a scalar extension of the 2HDM type-X. United States: N. p., 2015. Web. doi:10.1088/1475-7516/2015/10/025.
Hektor, Andi, Kannike, Kristjan, Marzola, Luca, & Institute of Physics, University of Tartu,Ravila 14c, Tartu, 50411. Muon g−2 and Galactic Centre γ-ray excess in a scalar extension of the 2HDM type-X. United States. doi:10.1088/1475-7516/2015/10/025.
Hektor, Andi, Kannike, Kristjan, Marzola, Luca, and Institute of Physics, University of Tartu,Ravila 14c, Tartu, 50411. 2015. "Muon g−2 and Galactic Centre γ-ray excess in a scalar extension of the 2HDM type-X". United States. doi:10.1088/1475-7516/2015/10/025.
@article{osti_22458393,
title = {Muon g−2 and Galactic Centre γ-ray excess in a scalar extension of the 2HDM type-X},
author = {Hektor, Andi and Kannike, Kristjan and Marzola, Luca and Institute of Physics, University of Tartu,Ravila 14c, Tartu, 50411},
abstractNote = {We consider an extension of the lepto-specific 2HDM with an extra singlet S as a dark matter candidate. Taking into account theoretical and experimental constraints, we investigate the possibility to address both the γ-ray excess detected at the Galactic Centre and the discrepancy between the Standard Model prediction and experimental results of the anomalous magnetic moment of the muon. Our analyses reveal that the SS→τ{sup +}τ{sup −} and SS→bb-bar channels reproduce the Galactic Centre excess, with an emerging dark matter candidate which complies with the bounds from direct detection experiments, measurements of the Higgs boson invisible decay width and observations of the dark matter relic abundance. Addressing the anomalous magnetic moment of the muon imposes further strong constraints on the model. Remarkably, under these conditions, the SS→bb-bar channel still allows for the fitting of the Galactic Centre. We also comment on a scenario allowed by the model where the SS→τ{sup +}τ{sup −} and SS→bb-bar channels have comparable branching ratios, which possibly yield an improved fitting of the Galactic Centre excess.},
doi = {10.1088/1475-7516/2015/10/025},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 10,
volume = 2015,
place = {United States},
year = 2015,
month =
}
  • We consider an extension of the lepto-specific 2HDM with an extra singlet S as a dark matter candidate. Taking into account theoretical and experimental constraints, we investigate the possibility to address both the γ-ray excess detected at the Galactic Centre and the discrepancy between the Standard Model prediction and experimental results of the anomalous magnetic moment of the muon. Our analyses reveal that the SS → τ{sup +} τ{sup −} and SS → b  b-bar channels reproduce the Galactic Centre excess, with an emerging dark matter candidate which complies with the bounds from direct detection experiments, measurements of the Higgs boson invisible decay width andmore » observations of the dark matter relic abundance. Addressing the anomalous magnetic moment of the muon imposes further strong constraints on the model. Remarkably, under these conditions, the SS → b  b-bar channel still allows for the fitting of the Galactic Centre. We also comment on a scenario allowed by the model where the SS → τ{sup +} τ{sup −} and SS → b  b-bar channels have comparable branching ratios, which possibly yield an improved fitting of the Galactic Centre excess.« less
  • Motivated by the recent indications for a 750 GeV resonance in the di-photon final state at the LHC, in this work we analyse the compatibility of the excess with the broad photon excess detected at the Galactic Centre. Intriguingly, by analysing the parameter space of an effective models where a 750 GeV pseudoscalar particles mediates the interaction between the Standard Model and a scalar dark sector, we prove the compatibility of the two signals. We show, however, that the LHC mono-jet searches and the Fermi LAT measurements strongly limit the viable parameter space. We comment on the possible impact ofmore » cosmic antiproton flux measurement by the AMS-02 experiment.« less
  • Several groups have recently claimed evidence for an unaccounted gamma-ray excess over the diffuse backgrounds at few GeV in the Fermi-LAT data in a region around the Galactic Center, consistent with a dark matter annihilation origin. We demonstrate that the main spectral and angular features of this excess can be reproduced if they are mostly due to inverse Compton emission from high-energy electrons injected in a burst event of ∼ 10{sup 52}÷10{sup 53} erg roughly O(10{sup 6}) years ago. We consider this example as a proof of principle that time-dependent phenomena need to be understood and accounted for—together with detailed diffuse foregrounds andmore » unaccounted ''steady state'' astrophysical sources—before any robust inference can be made about dark matter signals at the Galactic Center. In addition, we point out that the timescale suggested by our study, which controls both the energy cutoff and the angular extension of the signal, intriguingly matches (together with the energy budget) what is indirectly inferred by other evidences suggesting a very active Galactic Center in the past, for instance related to intense star formation and accretion phenomena.« less
  • Gamma-ray experiments using the imaging atmospheric Cherenkov technique have an angular resolution of typically better than 0.1 deg. per event in stereoscopic mode. The centroid of a point-source emitter, however, can be determined with higher precision, down to a few arcseconds for strong sources. This is of special interest when an excess could be due to several potential sources in the field of view. Here it is shown that H.E.S.S. achieves a pointing precision of 10 to 20 arcseconds by means of a mechanical pointing model. This is demonstrated by reconstructing the position of the AGN PKS 2155-304, which ismore » a point source emitter with a priori known position. The high precision allows to show that the TeV signal from the galactic centre region is consistent with the position of the galactic centre Sgr A*.« less