scholarly journals Symmergent Gravity, Seesawic New Physics, and Their Experimental Signatures

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Durmuş Demir
Keyword(s):  
Dark Matter ◽  
Gamma Rays ◽  
Planck Scale ◽  
New Physics ◽  
Fine Tuning ◽  
Dark Matter Candidate ◽  
Uv Sensitivity ◽  
Gauge Symmetries ◽  
The Standard Model ◽  
Zero Coupling

The standard model of elementary particles (SM) suffers from various problems, such as power-law ultraviolet (UV) sensitivity, exclusion of general relativity (GR), and absence of a dark matter candidate. The LHC experiments, according to which the TeV domain appears to be empty of new particles, started sidelining TeV-scale SUSY and other known cures of the UV sensitivity. In search for a remedy, in this work, it is revealed that affine curvature can emerge in a way restoring gauge symmetries explicitly broken by the UV cutoff. This emergent curvature cures the UV sensitivity and incorporates GR as symmetry-restoring emergent gravity (symmergent gravity, in brief) if a new physics sector (NP) exists to generate the Planck scale and if SM+NP is Fermi-Bose balanced. This setup, carrying fingerprints of trans-Planckian SUSY, predicts that gravity is Einstein (no higher-curvature terms), cosmic/gamma rays can originate from heavy NP scalars, and the UV cutoff might take right value to suppress the cosmological constant (alleviating fine-tuning with SUSY). The NP does not have to couple to the SM. In fact, NP-SM coupling can take any value from zero to ΛSM2/ΛNP2 if the SM is not to jump from ΛSM≈500  GeV to the NP scale ΛNP. The zero coupling, certifying an undetectable NP, agrees with all the collider and dark matter bounds at present. The seesawic bound ΛSM2/ΛNP2, directly verifiable at colliders, implies that (i) dark matter must have a mass ≲ΛSM, (ii) Higgs-curvature coupling must be ≈1.3%, (iii) the SM RGEs must remain nearly as in the SM, and (iv) right-handed neutrinos must have a mass ≲1000  TeV. These signatures serve as a concise testbed for symmergence.

scholarly journals The Search for Feebly Interacting Particles

2021 ◽  
Vol 71 (1) ◽  
pp. 279-313
Author(s):  
Gaia Lanfranchi ◽  
Maxim Pospelov ◽  
Philip Schuster
Keyword(s):  
Dark Matter ◽  
Particle Physics ◽  
Interaction Strength ◽  
New Physics ◽  
Fine Tuning ◽  
Experimental Program ◽  
Interacting Particles ◽  
Fundamental Physics ◽  
The Standard Model ◽  
The Universe

At the dawn of a new decade, particle physics faces the challenge of explaining the mystery of dark matter, the origin of matter over antimatter in the Universe, the apparent fine-tuning of the electroweak scale, and many other aspects of fundamental physics. Perhaps the most striking frontier to emerge in the search for answers involves New Physics at mass scales comparable to that of familiar matter—below the GeV scale but with very feeble interaction strength. New theoretical ideas to address dark matter and other fundamental questions predict such feebly interacting particles (FIPs) at these scales, and existing data may even provide hints of this possibility. Emboldened by the lessons of the LHC, a vibrant experimental program to discover such physics is underway, guided by a systematic theoretical approach that is firmly grounded in the underlying principles of the Standard Model. We give an overview of these efforts, their motivations, and the decadal goals that animate the community involved in the search for FIPs, and we focus in particular on accelerator-based experiments.

scholarly journals The tiny (g-2) muon wobble from small-μ supersymmetry

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Sebastian Baum ◽  
Marcela Carena ◽  
Nausheen R. Shah ◽  
Carlos E. M. Wagner
Keyword(s):  
Dark Matter ◽  
Direct Detection ◽  
Mass Parameter ◽  
New Physics ◽  
Higgs Bosons ◽  
Supersymmetric Model ◽  
Dark Matter Candidate ◽  
Muon Anomalous Magnetic Moment ◽  
The Standard Model ◽  
Direct Dark Matter

Abstract A new measurement of the muon anomalous magnetic moment, gμ− 2, has been reported by the Fermilab Muon g-2 collaboration and shows a 4.2 σ departure from the most precise and reliable calculation of this quantity in the Standard Model. Assuming that this discrepancy is due to new physics, we concentrate on a simple supersymmetric model that also provides a dark matter explanation in a previously unexplored region of supersymmetric parameter space. Such interesting region can realize a Bino-like dark matter candidate compatible with all current direct detection constraints for small to moderate values of the Higgsino mass parameter |μ|. This in turn would imply the existence of light additional Higgs bosons and Higgsino particles within reach of the high-luminosity LHC and future colliders. We provide benchmark scenarios that will be tested in the next generation of direct dark matter experiments and at the LHC.

scholarly journals A connection between flavour anomaly, neutrino mass, and axion

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Seungwon Baek
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Goldstone Boson ◽  
Mass Term ◽  
Higgs Doublet ◽  
New Physics ◽  
Fine Tuning ◽  
Spontaneous Breaking ◽  
Tree Level ◽  
Dark Matter Candidate

Abstract We propose a minimal model in which the flavour anomaly in the b → sμ+μ− transition is connected to the breaking of Peccei-Quinn (PQ) symmetry. The flavour anomaly is explained from new physics contribution by introducing one generation of heavy quark and heavy lepton which are vector-like under the standard model (SM) gauge group but charged under a local U(1)X group. They mix with the SM quarks and leptons, inducing flavour-changing Z′ couplings, which generates the b → sμ+μ− anomaly at tree level. On the other hand the new fermions are chiral under the global Peccei-Quinn(PQ) symmetry. The pseudo-Goldstone boson coming from the spontaneous breaking of the PQ symmetry becomes an axion, solving the strong CP problem and providing a cold dark matter candidate. The same symmetry prevents the right-handed neutrino from having a Majorana mass term. But the introduction of a neutrino-specific Higgs doublet allows neutrino to have Dirac mass term without fine-tuning problem. The model shows an interplay between axion, neutrino, dark matter, and flavour physics.

scholarly journals On a Possible Origin of the Gamma-ray Excess around the Galactic Center

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1432
Author(s):  
Dmitry O. Chernyshov ◽  
Andrei E. Egorov ◽  
Vladimir A. Dogiel ◽  
Alexei V. Ivlev
Keyword(s):  
Dark Matter ◽  
Gamma Rays ◽  
Molecular Clouds ◽  
Alternative Explanation ◽  
Gamma Ray ◽  
Galactic Center ◽  
The Self ◽  
Large Area ◽  
Mhd Turbulence ◽  
The Standard Model

Recent observations of gamma rays with the Fermi Large Area Telescope (LAT) in the direction of the inner galaxy revealed a mysterious excess of GeV. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs) generation and propagation with a peak in the spectrum around a few GeV. Popular interpretations of this excess are that it is due to either spherically distributed annihilating dark matter (DM) or an abnormal population of millisecond pulsars. We suggest an alternative explanation of the excess through the CR interactions with molecular clouds in the Galactic Center (GC) region. We assumed that the excess could be imitated by the emission of molecular clouds with depleted density of CRs with energies below ∼10 GeV inside. A novelty of our work is in detailed elaboration of the depletion mechanism of CRs with the mentioned energies through the “barrier” near the cloud edge formed by the self-excited MHD turbulence. This depletion of CRs inside the clouds may be a reason for the deficit of gamma rays from the Central Molecular Zone (CMZ) at energies below a few GeV. This in turn changes the ratio between various emission components at those energies and may potentially absorb the GeV excess by a simple renormalization of key components.

scholarly journals R-PARITY VIOLATING U(1)′-EXTENDED SUPERSYMMETRIC STANDARD MODEL

2008 ◽  
Vol 23 (39) ◽  
pp. 3271-3283 ◽  
Author(s):  
HYE-SUNG LEE
Keyword(s):  
Dark Matter ◽  
Gauge Symmetry ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Discrete Symmetries ◽  
Discrete Symmetry ◽  
New Physics ◽  
Dark Matter Candidate ◽  
Hidden Sector

Supersymmetry is one of the best motivated new physics scenarios. To build a realistic supersymmetric standard model, however, a companion symmetry is necessary to address various issues. While R-parity is a popular candidate that can address the proton and dark matter issues simultaneously, it is not the only option for such a property. We review how a TeV scale U(1)′ gauge symmetry can replace the R-parity. Discrete symmetries of the U(1)′ can make the model still viable and attractive with distinguishable phenomenology. For instance, with a residual discrete symmetry of the U(1)′, Z6 = B3 × U2, the proton can be protected by the baryon triality (B3) and a hidden sector dark matter candidate can be protected by the U-parity (U2).

scholarly journals CP VIOLATIONS (AND MORE) AFTER THE FIRST TWO YEARS OF LHCB

2013 ◽  
Vol 53 (A) ◽  
pp. 528-533
Author(s):  
Giulio Auriemma
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Particle Physics ◽  
Hadron Collider ◽  
Higgs Sector ◽  
New Physics ◽  
Baryon Asymmetry ◽  
Open Problems ◽  
Cp Violations ◽  
The Standard Model

The most interesting cosmological open problems, baryon asymmetry, dark matter, inflation and dark energy, are not explained by the standard model of particle physics (SM). The final<br />goal of the Large Hadron Collider an experimental verification of the SM in the Higgs sector, and also a search for evidence of new physics beyond it. In this paper we will report some of the results obtained in 2010 and 2011, from the LHCb experiment dedicated to the study of CP violations and rare decays of heavy quarks.

THREE GENERATIONS: A PREDICTION FULFILLED

1990 ◽  
Vol 05 (09) ◽  
pp. 645-651
Author(s):  
JORGE L. LOPEZ ◽  
D.V. NANOPOULOS
Keyword(s):  
Dark Matter ◽  
Strong Correlation ◽  
Planck Scale ◽  
New Physics ◽  
Supersymmetric Particle ◽  
Three Generations ◽  
Unified Theories ◽  
The Universe

We recall the theoretical arguments that led us more than ten years ago to predict that there are only three generations. Quark-lepton mass relations (mb/mτ ≈ 2.8), as universally come out from unified theories at superhigh energies (close to the Planck scale), are the key point. We further argue that fractional deviations from Nν=3 may signal new physics. The supersymmetric decay Z→ÑÑ, with Ñ the lightest neutralino and lightest supersymmetric particle (LSP), easily fits the bill. In the specific case of flipped (SU(5)×U(1)) unification, there is a strong correlation between mt≈ O(90 ± 10) GeV, slepton masses of O(50 GeV) and the closure of the Universe due to Ñ dark matter, while ΔNν ≈ (0.1–0.5).

scholarly journals Big Bang Nucleosynthesis in Visible and Hidden-Mirror Sectors

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Paolo Ciarcelluti
Keyword(s):  
Dark Matter ◽  
Building Blocks ◽  
Big Bang ◽  
Dark Matter Candidate ◽  
Big Bang Nucleosynthesis ◽  
Enhanced Production ◽  
The Standard Model ◽  
The Big Bang ◽  
The Universe ◽  
Mirror Matter

One of the still viable candidates for the dark matter is the so-called mirror matter. Its cosmological and astrophysical implications were widely studied, pointing out the importance to go further with research. In particular, the Big Bang nucleosynthesis provides a strong test for every dark matter candidate, since it is well studied and involves relatively few free parameters. The necessity of accurate studies of primordial nucleosynthesis with mirror matter has then emerged. I present here the results of accurate numerical simulations of the primordial production of both ordinary nuclides and nuclides made of mirror baryons, in presence of a hidden mirror sector with unbroken parity symmetry and with gravitational interactions only. These elements are the building blocks of all the structures forming in the Universe; therefore, their chemical composition is a key ingredient for astrophysics with mirror dark matter. The production of ordinary nuclides shows differences from the standard model for a ratio of the temperatures between mirror and ordinary sectorsx=T′/T≳0.3, and they present an interesting decrease of the abundance ofLi7. For the mirror nuclides, instead, one observes an enhanced production ofHe4, which becomes the dominant element forx≲0.5, and much larger abundances of heavier elements.

scholarly journals SUPERSYMMETRIC U(1) GAUGE REALIZATION OF THE DARK SCALAR DOUBLET MODEL OF RADIATIVE NEUTRINO MASS

2008 ◽  
Vol 23 (10) ◽  
pp. 721-725 ◽  
Author(s):  
ERNEST MA
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Neutrino Mass ◽  
Dark Matter Candidate ◽  
Neutrino Masses ◽  
Particle Interactions ◽  
The Standard Model ◽  
Doublet Model

Adding a second scalar doublet (η+, η0) and three neutral singlet fermions N1, 2, 3 to the Standard Model of particle interactions with a new Z2 symmetry, it has been shown that [Formula: see text] or [Formula: see text] is a good dark-matter candidate and seesaw neutrino masses are generated radiatively. A supersymmetric U(1) gauge extension of this new idea is proposed, which enforces the usual R-parity of the Minimal Supersymmetric Standard Model, and allows this new Z2 symmetry to emerge as a discrete remnant.

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