scholarly journals Search for Light New Physics atBFactories

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Bertrand Echenard
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
New Physics ◽  
Large Datasets ◽  
Higgs Bosons ◽  
The Standard Model ◽  
New Particles

Many extensions of the Standard Model include the possibility of light new particles, such as light Higgs bosons or dark matter candidates. These scenarios can be probed using the large datasets collected byBfactories, complementing measurements performed at the LHC. This paper summarizes recent searches for light new physics conducted by theBABARand Belle experiments.

ASTROPARTICLE PHYSICS

2007 ◽  
Vol 22 (30) ◽  
pp. 5550-5560
Author(s):  
A. BETTINI
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Experimental Evidence ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Astroparticle Physics ◽  
The Standard Model ◽  
New Particles

Astroparticle is a very wide, expanding, sector of Physics; this report covers only a fraction of it complementing the plenary reports of Y. Takahashi and K. Inoue. I will focus, in particular, on the experimental evidence of new physics, beyond the Standard Model. Astroparticle and accelerator experiments will give complementary tools in the search of new particles, like those of the dark matter, and new fundamental fields, like the inflaton.

scholarly journals SEARCHES FOR NEW PARTICLES

2002 ◽  
Vol 17 (23) ◽  
pp. 3336-3351 ◽  
Author(s):  
GAIL G. HANSON
Keyword(s):  
Standard Model ◽  
Top Quark ◽  
New Physics ◽  
Higgs Bosons ◽  
Standard Model Higgs Boson ◽  
The Past ◽  
Flavor Changing ◽  
The Standard Model ◽  
The Status ◽  
New Particles

The status of searches for new particles and new physics during the past year at the Fermilab Tevatron, at HERA and at LEP is summarized. A discussion of the hints for the Standard Model Higgs boson from LEP2 data is presented. Searches for non-Standard Model Higgs bosons are also described. Many searches have been carried out for the particles predicted by supersymmetry theories, and a sampling of these is given. There have also been searches for flavor changing neutral currents in the interactions of the top quark. In addition, searches for excited leptons, leptoquarks and technicolor are summarized.

scholarly journals Explaining Dark Matter Without New Physics?

2020 ◽  
Author(s):  
Stephane Maes
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Long Range ◽  
New Physics ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
New Particles

In a multi-fold universe, gravity emerges from entanglement through the multi-fold mechanisms. As a result, gravity-like effects appear in between entangled particles or regions. When applied to astrophysics, these effects are analogous to additional matter within or around galaxies. This way, we recover behaviors that match expected and observed effects when dark matter would be present or missing. No New Physics is introduced in terms of new particles beyond the Standard Model or modifying long range gravity: only the modeling of gravity as emerging from entanglement, in a multi-fold universe.

scholarly journals The history of the muon (g-2) experiments

2019 ◽  
Author(s):  
B. Lee Roberts
Keyword(s):  
Standard Model ◽  
Quantum Electrodynamics ◽  
National Laboratory ◽  
New Physics ◽  
Brookhaven National Laboratory ◽  
Muon Decay ◽  
Higgs Bosons ◽  
The Standard Model ◽  
History Of ◽  
First Time

I discuss the history of the muon (g-2)(g−2) measurements, beginning with the Columbia-Nevis measurement that observed parity violation in muon decay, and also measured the muon gg-factor for the first time, finding g_\mu=2gμ=2. The theoretical (Standard Model) value contains contributions from quantum electrodynamics, the strong interaction through hadronic vacuum polarization and hadronic light-by-light loops, as well as the electroweak contributions from the WW, ZZ and Higgs bosons. The subsequent experiments, first at Nevis and then with increasing precision at CERN, measured the muon anomaly a_\mu = (g_\mu-2)/2aμ=(gμ−2)/2 down to a precision of 7.3 parts per million (ppm). The Brookhaven National Laboratory experiment E821 increased the precision to 0.54 ppm, and observed for the first time the electroweak contributions. Interestingly, the value of a_\muaμ measured at Brookhaven appears to be larger than the Standard Model value by greater than three standard deviations. A new experiment, Fermilab E989, aims to improve on the precision by a factor of four, to clarify whether this result is a harbinger of new physics entering through loops, or from some experimental, statistical or systematic issue.

scholarly journals Searches for new physics with free neutrons and radioactive atomic nuclei

2021 ◽  
Vol 52 (4) ◽  
pp. 22-25
Author(s):  
N. Severijns
Keyword(s):  
Standard Model ◽  
Particle Physics ◽  
New Physics ◽  
Low Energy ◽  
Atomic Nuclei ◽  
The Standard Model ◽  
New Particles

The Standard Model of Particle Physics is very successful but does not explain several experimental observations. Extensions of it, invoking new particles or phenomena, could overcome this. Experiments in different energy domains allow testing these extensions and searching for new particles. Here focus is on low-energy experiments with neutrons and radioactive nuclei.

scholarly journals Electroweak symmetry non-restoration from dark matter

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Oleksii Matsedonskyi ◽  
James Unwin ◽  
Qingyun Wang
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Higgs Mass ◽  
Direct Detection ◽  
Higgs Doublet ◽  
New Physics ◽  
Electroweak Symmetry ◽  
The Standard Model ◽  
New States ◽  
Potential Remedy

Abstract Restoration of the electroweak symmetry at temperatures around the Higgs mass is linked to tight phenomenological constraints on many baryogenesis scenarios. A potential remedy can be found in mechanisms of electroweak symmetry non-restoration (SNR), in which symmetry breaking is extended to higher temperatures due to new states with couplings to the Standard Model. Here we show that, in the presence of a second Higgs doublet, SNR can be realized with only a handful of new fermions which can be identified as viable dark matter candidates consistent with all current observational constraints. The competing requirements on this class of models allow for SNR at temperatures up to ∼TeV, and imply the presence of sub-TeV new physics with sizable interactions with the Standard Model. As a result this scenario is highly testable with signals in reach of next-generation collider and dark matter direct detection experiments.

scholarly journals Type-I 2HDM under the Higgs and electroweak precision measurements

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Ning Chen ◽  
Tao Han ◽  
Shuailong Li ◽  
Shufang Su ◽  
Wei Su ◽  
...  
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
New Physics ◽  
Higgs Bosons ◽  
Precision Measurements ◽  
Tree Level ◽  
Type I ◽  
Loop Level ◽  
The Standard Model ◽  
Parameter Ranges

Abstract We explore the extent to which future precision measurements of the Standard Model (SM) observables at the proposed Z-factories and Higgs factories may have impacts on new physics beyond the Standard Model, as illustrated by studying the Type-I Two-Higgs-doublet model (Type-I 2HDM). We include the contributions from the heavy Higgs bosons at the tree-level and at the one-loop level in a full model-parameter space. While only small tan β region is strongly constrained at tree level, the large tan β region gets constrained at loop level due to tan β enhanced tri-Higgs couplings. We perform a multiple variable χ2 fit with non-alignment and non-degenerate masses. We find that the allowed parameter ranges could be tightly constrained by the future Higgs precision measurements, especially for small and large values of tan β. Indirect limits on the masses of heavy Higgs bosons can be obtained, which can be complementary to the direct searches of the heavy Higgs bosons at hadron colliders. We also find that the expected accuracies at the Z-pole and at a Higgs factory are quite complementary in constraining mass splittings of heavy Higgs bosons. The typical results are | cos(β − α)| < 0.05, |∆mΦ| < 200 GeV, and tan β ≳ 0.3. The reaches from CEPC, Fcc-ee and ILC are also compared, for both Higgs and Z-pole precision measurements. Comparing to the Type-II 2HDM, the 95% C.L. allowed range of cos(β − α) is larger, especially for large values of tan β.

scholarly journals SU(2)N model of vector dark matter with a leptonic connection

2015 ◽  
Vol 30 (03) ◽  
pp. 1550018 ◽  
Author(s):  
Sean Fraser ◽  
Ernest Ma ◽  
Mohammadreza Zakeri
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Cross Section ◽  
Neutrino Mass ◽  
Thermal Equilibrium ◽  
Seesaw Mechanism ◽  
The Standard Model ◽  
Relic Abundance ◽  
New Particles

Models of fermion and scalar dark matter abound. Here we consider instead vector dark matter, from an SU(2)N extension of the standard model. It has a number of interesting properties, including a possible implementation of the inverse seesaw mechanism for neutrino mass. The annihilation of dark matter for calculating its relic abundance in this model is not dominated by its cross-section to standard-model particles, but rather to other new particles which are in thermal equilibrium with those of the standard model.

MONOJET EVENTS: FROM DARK MATTER TO EXTRA DIMENSIONS, A SEARCH FOR THE EXOTICS USING THE STANDARD MODEL

2013 ◽  
Vol 28 (08) ◽  
pp. 1330012
Author(s):  
PIERRE-HUGUES BEAUCHEMIN ◽  
REYHANEH REZVANI
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Extra Dimensions ◽  
Transverse Energy ◽  
Large Extra Dimensions ◽  
High Energy ◽  
New Physics ◽  
High Transverse Momentum ◽  
Final State ◽  
The Standard Model

Monojet events consist in event topologies with a high transverse momentum jet and a large amount of missing transverse energy. They constitute a promising final state that could lead to phenomena beyond the Standard Model. The theoretical models giving rise to such a signature include the pair production of Weakly Interacting Massive Particles, as dark matter candidates, and models of large extra dimensions. Monojet events can even be used to measure the Standard Model properties of Z boson decays, provided that the precision of the analysis is high enough. Such precision can be achieved by using data-driven determinations of the Standard Model contributions to monojet events. Exotics searches for new physics in such a final state have been performed at all high energy hadronic collider experiments since SPS. The ATLAS and CMS analyses with 7 TeV LHC data provide the latest and most useful information obtained from monojet studies. Their results are presented and discussed in this review paper.

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