scholarly journals The Tensor and the Scalar Charges of the Nucleon from Hadron Phenomenology

2018 ◽  
Vol 172 ◽  
pp. 03007
Author(s):  
A. Courtoy
Keyword(s):  
Standard Model ◽  
Spin Asymmetry ◽  
Beyond The Standard Model ◽  
Scalar Charge ◽  
The Standard Model ◽  
Asymmetry Data ◽  
Fragmentation Functions ◽  
The Impact ◽  
Beam Spin Asymmetry

We discuss the impact of the determination of the nucleon tensor charge on searches for physics Beyond the Standard Model. We also comment on the future extraction of the subleading-twist PDF e(x) from Jefferson Lab soon-to-be-released Beam Spin Asymmetry data as well as from the expected data of CLAS12 and SoLID, as the latter is related to the scalar charge. These analyses are possible through the phenomenology of Dihadron Fragmentation Functions related processes, which we report on here as well.

scholarly journals Precision Electroweak Data: Present Status and Future Prospects

1997 ◽  
Vol 12 (23) ◽  
pp. 4109-4154 ◽  
Author(s):  
Peter B. Renton
Keyword(s):  
Standard Model ◽  
Present Status ◽  
Model Parameters ◽  
Second Phase ◽  
Independent Variables ◽  
The Standard Model ◽  
Model Independent ◽  
The Impact ◽  
Precision Electroweak Data

The present status of precision electroweak data is reviewed. These data include LEP measurements of the mass and width of the Z, together with various measurements on the Z-fermion couplings. These data are compared to, and combined with, data from the SLC on the left–right polarized asymmetry, A LR , and the left–right forward–backward asymmetries for b and c quarks. These measurements are combined with hadron collider measurements from the Tevatron and CERN on the mass of the W boson, mW, as well as other electroweak data, in global electroweak fits in which various Standard Model parameters are determined. A comparison is made between the results of direct measurements of mW and the top-quark mass, mt, as determined from the Tevatron, with the indirect results coming from electroweak radiative corrections. Using all precision electroweak data, fits are also made to determine limits on the mass of the Higgs boson, mH. The influence on these limits of specific measurements, particularly those which are somewhat inconsistent with the Standard Model, is explored. The data are also analyzed in terms of the quasi model independent ∊ variables. Improvements in the determination of all of these quantities are expected when the Z data at LEP are fully analyzed, and further measurements on A LR and related asymmetries performed at the SLC. In addition, substantial improvements in the determination of mW are expected from measurements at the Tevatron and in the second phase of LEP. An estimate is made of the likely precision of these data, and the implications of the impact of these data on precision electroweak tests are discussed. This discussion is made both in terms of the Standard Model and also in the context of the quasi model independent ∊ variables.

BIG BANG NUCLEOSYNTHESIS: AN UPDATE

1996 ◽  
Vol 11 (03) ◽  
pp. 409-428 ◽  
Author(s):  
KEITH A. OLIVE ◽  
SEAN T. SCULLY
Keyword(s):  
Standard Model ◽  
Light Element ◽  
Big Bang ◽  
Current Status ◽  
Beyond The Standard Model ◽  
Effective Number ◽  
Big Bang Nucleosynthesis ◽  
Element Abundances ◽  
The Standard Model

The current status of big bang nucleosynthesis is reviewed with an emphasis on the comparison between the observational determination of the light element abundances of D , 3 He , 4 He and 7 Li and the predictions from theory. In particular, we present new analyses for 4 He and 7 Li . Implications for physics beyond the standard model are also discussed. In addition, limits on the effective number of neutrino flavors are updated.

scholarly journals Scalar leptoquark effects on $$B \rightarrow \mu \bar{\nu }$$ decay

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Wei-Shu Hou ◽  
Tanmoy Modak ◽  
Gwo-Guang Wong
Keyword(s):  
Standard Model ◽  
Parameter Space ◽  
Low Energy ◽  
Beyond The Standard Model ◽  
Meson Decays ◽  
Scalar Leptoquark ◽  
The Standard Model ◽  
The Impact ◽  
Energy Physics

AbstractPurely leptonic B meson decays provide unique probes for physics Beyond the Standard Model. We study the impact of a scalar leptoquark, $$S_1$$S1, on $$B \rightarrow \mu \bar{\nu }$$B→μν¯ decay. We find that, for $$m_{S_1}\sim 1\ \hbox {TeV}$$mS1∼1TeV, the $$S_1$$S1 leptoquark can modify the $$B \rightarrow \mu \bar{\nu }$$B→μν¯ rate significantly. Such a leptoquark can in principle also alter the $$B \rightarrow \tau \bar{\nu }$$B→τν¯ rate. However, current searches from LHC and low energy physics provide some constraints on the parameter space.

scholarly journals Developments in Rare Kaon Decay Physics

2000 ◽  
Vol 50 (1) ◽  
pp. 249-297 ◽  
Author(s):  
A.R. Barker ◽  
S.H. Kettell
Keyword(s):  
Standard Model ◽  
New Physics ◽  
High Mass ◽  
Current Status ◽  
Model Parameters ◽  
Beyond The Standard Model ◽  
Kaon Decay ◽  
Kaon Decays ◽  
The Standard Model

▪ Abstract  We review the current status of the field of rare kaon decays. The study of rare kaon decays has played a key role in the development of the standard model, and the field continues to have significant impact. The two areas of greatest import are the search for physics beyond the standard model and the determination of fundamental standard-model parameters. Due to the exquisite sensitivity of rare kaon decay experiments, searches for new physics can probe very high mass scales. Studies of the K → π ν[Formula: see text] modes in particular, where the first event has recently been seen, will permit tests of the standard-model picture of quark mixing and CP violation.

scholarly journals Determination of e+e- beam polarization for optimal gauge boson discovery limits

2015 ◽  
Vol 30 (14) ◽  
pp. 1550075
Author(s):  
Ali A. Bagneid
Keyword(s):  
Standard Model ◽  
Gauge Boson ◽  
Electron Beams ◽  
Beam Polarization ◽  
Beyond The Standard Model ◽  
Gauge Bosons ◽  
Maximum Value ◽  
The Standard Model ◽  
Single Set

Extra neutral gauge bosons suggested by models beyond the standard model can indirectly show up in e+e- collisions through off-resonance deviations of various physical observables from the corresponding standard model values. We considered leptonic observables and studied the dependence of the deviations on the polarizations of the positron and electron beams. We showed that, for a given model, the magnitude of the deviation of a given observable can attain its maximum value if the polarizations of the positron and electron beams are properly chosen. We determined, for a given model, a single set of beam polarization so that if this set is employed in measuring all considered observables, it produces the highest extra gauge boson discovery limits.

scholarly journals Electroweak phase transitions with BSM fermions

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Martin Gabelmann ◽  
M. Margarete Mühlleitner ◽  
Jonas Müller
Keyword(s):  
Standard Model ◽  
Degrees Of Freedom ◽  
Higgs Doublet ◽  
Beyond The Standard Model ◽  
Electroweak Phase Transition ◽  
The Standard Model ◽  
Light Scalar ◽  
Doublet Model ◽  
Split Supersymmetry ◽  
The Impact

Abstract We study the impact of additional beyond-the-Standard Model (BSM) fermions, charged under the Standard Model (SM) SU(2)L ⊗ U(1)Y gauge group, on the electroweak phase transition (EWPT) in a 2-Higgs-Doublet-Model (2HDM) of type II. We find that the strength of the EWPT can be enhanced by about 40% compared to the default 2HDM. Therefore, additional light fermions are a useful tool to weaken the tension between increasing mass constraints on BSM scalars and the requirement of additional light scalar degrees of freedom to accommodate a strong first order EWPT. The findings are of particular interest for a variety of (non-minimal) split supersymmetry scenarios which necessarily introduce additional light fermion degrees of freedom.

Beyond the Standard Model

2017 ◽  
Author(s):  
Laurent Baulieu ◽  
John Iliopoulos ◽  
Roland Sénéor
Keyword(s):  
Field Theory ◽  
General Relativity ◽  
Supergravity Models ◽  
Standard Model ◽  
Field Theories ◽  
Beyond The Standard Model ◽  
Super Symmetry ◽  
The Standard Model ◽  
Topological Field ◽  
Supersymmetric Theories

The motivation for supersymmetry. The algebra, the superspace, and the representations. Field theory models and the non-renormalisation theorems. Spontaneous and explicit breaking of super-symmetry. The generalisation of the Montonen–Olive duality conjecture in supersymmetric theories. The remarkable properties of extended supersymmetric theories. A brief discussion of twisted supersymmetry in connection with topological field theories. Attempts to build a supersymmetric extention of the standard model and its experimental consequences. The property of gauge supersymmetry to include general relativity and the supergravity models.

scholarly journals Search for dark matter in association with an energetic photon in pp collisions at $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Dark Matter ◽  
Transverse Momentum ◽  
Standard Model ◽  
Confidence Level ◽  
Axial Vector ◽  
Beyond The Standard Model ◽  
Proton Proton ◽  
Missing Transverse Momentum ◽  
Upper Limits ◽  
The Standard Model

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.

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