scholarly journals Shedding light on dark matter with recent muon (g − 2) and Higgs exotic decay measurements

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Chih-Ting Lu ◽  
Raymundo Ramos ◽  
Yue-Lin Sming Tsai

Abstract Recently, we have witnessed two hints of physics beyond the standard model: a 3.3σ local excess ($$ {M}_{A_0} $$ M A 0 = 52 GeV) in the search for H0 → A0A0 → b$$ \overline{b} $$ b ¯ μ+μ− and a 4.2σ deviation from the SM prediction in the (g − 2)μ measurement. The first excess was found by the ATLAS collaboration using 139 fb−1 data at $$ \sqrt{s} $$ s = 13 TeV. The second deviation is a combination of the results from the Brookhaven E821 and the recently reported Fermilab E989 experiment. We attempt to explain these deviations in terms of a renormalizable simplified dark matter model. Inspired by the null signal result from dark matter (DM) direct detection, we interpret the possible new particle, A0, as a pseudoscalar mediator connecting DM and the standard model. On the other hand, a new vector-like muon lepton can explain these two excesses at the same time while contributing to the DM phenomenology.

2015 ◽  
Vol 59 (6) ◽  
pp. 491-493 ◽  
Author(s):  
M. Demiański ◽  
A. G. Doroshkevich

Author(s):  
Junji Hisano

It is now certain that dark matter exists in the Universe. However, we do not know its nature, nor are there dark matter candidates in the standard model of particle physics or astronomy However, weakly interacting massive particles (WIMPs) in models beyond the standard model are one of the leading candidates available to provide explanation. The dark matter direct detection experiments, in which the nuclei recoiled by WIMPs are sought, are one of the methods to elucidate the nature of dark matter. This chapter introduces an effective field theory (EFT) approach in order to evaluate the nucleon–WIMP elastic scattering cross section.


2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Tanushree Basak ◽  
Baradhwaj Coleppa ◽  
Kousik Loho

Abstract We revisit the two real singlet extension of the Standard Model with a $$ {Z}_2\times {Z}_2^{\prime } $$ Z 2 × Z 2 ′ symmetry. One of the singlet scalars S2, by virtue of an unbroken $$ {Z}_2^{\prime } $$ Z 2 ′ symmetry, plays the role of a stable dark matter candidate. The other scalar S1, with spontaneously broken Z2-symmetry, mixes with the SM Higgs boson and acts as the scalar mediator. We analyze the model by putting in the entire set of theoretical and recent experimental constraints. The latest bounds from direct detection Xenon1T experiment severely restricts the allowed region of parameter space of couplings. To ensure the dark matter satisfies the relic abundance criterion, we rely on the Breit-Wigner enhanced annihilation cross-section. Further, we study the viability of explaining the observed gamma-ray excess in the galactic center in this model with a dark matter of mass in the ∼ 36 − 51 GeV window and present our conclusions.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  

Abstract A search for dark matter is conducted in final states containing a photon and missing transverse momentum in proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV. The data, collected during 2015–2018 by the ATLAS experiment at the CERN LHC, correspond to an integrated luminosity of 139 fb−1. No deviations from the predictions of the Standard Model are observed and 95% confidence-level upper limits between 2.45 fb and 0.5 fb are set on the visible cross section for contributions from physics beyond the Standard Model, in different ranges of the missing transverse momentum. The results are interpreted as 95% confidence-level limits in models where weakly interacting dark-matter candidates are pair-produced via an s-channel axial-vector or vector mediator. Dark-matter candidates with masses up to 415 (580) GeV are excluded for axial-vector (vector) mediators, while the maximum excluded mass of the mediator is 1460 (1470) GeV. In addition, the results are expressed in terms of 95% confidence-level limits on the parameters of a model with an axion-like particle produced in association with a photon, and are used to constrain the coupling gaZγ of an axion-like particle to the electroweak gauge bosons.


2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Maximilian Ruhdorfer ◽  
Ennio Salvioni ◽  
Andreas Weiler

We study for the first time the collider reach on the derivative Higgs portal, the leading effective interaction that couples a pseudo Nambu-Goldstone boson (pNGB) scalar Dark Matter to the Standard Model. We focus on Dark Matter pair production through an off-shell Higgs boson, which is analyzed in the vector boson fusion channel. A variety of future high-energy lepton colliders as well as hadron colliders are considered, including CLIC, a muon collider, the High-Luminosity and High-Energy versions of the LHC, and FCC-hh. Implications on the parameter space of pNGB Dark Matter are discussed. In addition, we give improved and extended results for the collider reach on the marginal Higgs portal, under the assumption that the new scalars escape the detector, as motivated by a variety of beyond the Standard Model scenarios.


2015 ◽  
Vol 24 (07) ◽  
pp. 1530019 ◽  
Author(s):  
Mathias Garny ◽  
Alejandro Ibarra ◽  
Stefan Vogl

Three main strategies are being pursued to search for nongravitational dark matter signals: direct detection, indirect detection and collider searches. Interestingly, experiments have reached sensitivities in these three search strategies which may allow detection in the near future. In order to take full benefit of the wealth of experimental data, and in order to confirm a possible dark matter signal, it is necessary to specify the nature of the dark matter particle and of the mediator to the Standard Model. In this paper, we focus on a simplified model where the dark matter particle is a Majorana fermion that couples to a light Standard Model fermion via a Yukawa coupling with a scalar mediator. We review the observational signatures of this model and we discuss the complementarity among the various search strategies, with emphasis in the well motivated scenario where the dark matter particles are produced in the early universe via thermal freeze-out.


2018 ◽  
Vol 33 (10n11) ◽  
pp. 1830007 ◽  
Author(s):  
Agnieszka Ilnicka ◽  
Tania Robens ◽  
Tim Stefaniak

We give a brief overview of beyond the Standard Model (BSM) theories with an extended scalar sector and their phenomenological status in the light of recent experimental results. We discuss the relevant theoretical and experimental constraints, and show their impact on the allowed parameter space of two specific models: the real scalar singlet extension of the Standard Model (SM) and the Inert Doublet Model. We emphasize the importance of the LHC measurements, both the direct searches for additional scalar bosons, as well as the precise measurements of properties of the Higgs boson of mass 125 GeV. We show the complementarity of these measurements to electroweak and dark matter observables.


Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 587 ◽  
Author(s):  
Vitaly Beylin ◽  
Maxim Yu. Khlopov ◽  
Vladimir Kuksa ◽  
Nikolay Volchanskiy

The problems of simple elementary weakly interacting massive particles (WIMPs) appeal to extend the physical basis for nonbaryonic dark matter. Such extension involves more sophisticated dark matter candidates from physics beyond the Standard Model (BSM) of elementary particles. We discuss several models of dark matter, predicting new colored, hyper-colored or techni-colored particles and their accelerator and non-accelerator probes. The nontrivial properties of the proposed dark matter candidates can shed new light on the dark matter physics. They provide interesting solutions for the puzzles of direct and indirect dark matter search.


2010 ◽  
Vol 25 (02n03) ◽  
pp. 564-572
Author(s):  
MAXIM POSPELOV

I consider models of light super-weakly interacting cold dark matter, with [Formula: see text] mass, focusing on bosonic candidates such as pseudoscalars and vectors. I analyze the cosmological abundance, the γ-background created by particle decays, the impact on stellar processes due to cooling, and the direct detection capabilities in order to identify classes of models that pass all the constraints. In certain models, variants of photoelectric (or axioelectric) absorption of dark matter in direct-detection experiments can provide a sensitivity to the superweak couplings to the Standard Model which is superior to all existing indirect constraints. In all models studied, the annual modulation of the direct-detection signal is at the currently unobservable level of O(10-5).


LEP data constrain severely many proposed extensions of the Standard Model. These include: massive neutrinos, which are now largely excluded as candidates for the dark matter of the Universe; supersymmetric particles, the lightest of which would still constitute detectable dark matter; technicolour, of which many favoured versions are now excluded by precision electroweak measurements; and grand unified theories, of which LEP data favour supersymmetric versions.


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