ANOMALY CANCELLATION IMPLICATION FOR Z′ DECAY TO FERMION PAIR

2011 ◽  
Vol 26 (29) ◽  
pp. 2201-2211
Author(s):  
YING ZHANG
Keyword(s):  
Decay Width ◽  
Z Boson ◽  
Axial Vector ◽  
Branching Ratio ◽  
Anomaly Cancellation ◽  
Sum Rule ◽  
Fermion Pair ◽  
Charge Assignment ◽  
Decay Widths ◽  
Left Right Asymmetry

Z′ boson vector and axial vector couplings to fermions are studied in terms of anomaly cancellation in the condition of small Z–Z′ mixing. The anomaly-free U(1)′ charge assignment that parametrized by two independent charges is proposed. Z′ decay width to fermion pair [Formula: see text], hadron-to-lepton ratio [Formula: see text], hadron branching ratio [Formula: see text], left–right asymmetry [Formula: see text] and forward–backward asymmetry [Formula: see text] are investigated. A special sum rule of Z′ decay widths is also derived.

scholarly journals Semileptonic decay of $$\varOmega _c^0 \rightarrow \varXi ^- l^+ \nu _l$$ from light-cone sum rules

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Hui-Hui Duan ◽  
Yong-Lu Liu ◽  
Ming-Qiu Huang
Keyword(s):  
Decay Width ◽  
Light Cone ◽  
Sum Rules ◽  
Semileptonic Decay ◽  
Decay Channel ◽  
Branching Ratio ◽  
Form Factors ◽  
Weak Decay ◽  
Decay Process ◽  
Sum Rule

AbstractThe weak decay process of $$\varOmega _c$$ Ω c to $$\varXi $$ Ξ is calculated in the method of QCD light-cone sum rule. The decay width of $$\varOmega _c^0 \rightarrow \varXi ^- l^+ \nu _l$$ Ω c 0 → Ξ - l + ν l and its decay branching ratio are also calculated with the form factors from this work’s calculation. To the twist-6 distribution amplitudes, the form factors $$f_1=0.66\pm 0.02, f_2=-0.76\pm 0.03, g_1=0.06\pm 0.01$$ f 1 = 0.66 ± 0.02 , f 2 = - 0.76 ± 0.03 , g 1 = 0.06 ± 0.01 and $$g_2=-0.44\pm 0.01$$ g 2 = - 0.44 ± 0.01 are given at zero recoil point. The result of the semileptonic decay width of $$\varOmega _c^0 \rightarrow \varXi ^-l^+\nu _l$$ Ω c 0 → Ξ - l + ν l is $$\varGamma =(7.51\pm 0.36)\times 10^{-15}~\mathrm{{GeV}}$$ Γ = ( 7.51 ± 0.36 ) × 10 - 15 GeV , and the prediction of the decay branching ratio $$Br(\varOmega _c^0\rightarrow \varXi ^-l^+\nu _l)=(3.06\pm 0.15)\times 10^{-3}$$ B r ( Ω c 0 → Ξ - l + ν l ) = ( 3.06 ± 0.15 ) × 10 - 3 . These results fit well with other works, and the decay width and branching ratio are improved. This not too small branching ratio gives a good direction to explore this decay channel in the future experiments.

scholarly journals NEW PHYSICS UPPER BOUND ON THE BRANCHING RATIO OF Bs → l+l-γ

2007 ◽  
Vol 22 (18) ◽  
pp. 1319-1328 ◽  
Author(s):  
ASHUTOSH KUMAR ALOK ◽  
S. UMA SANKAR
Keyword(s):  
Upper Bound ◽  
Axial Vector ◽  
Branching Ratio ◽  
New Physics ◽  
Large Contribution ◽  
Beyond The Standard Model ◽  
Standard Model Expectation ◽  
Model Expectation ◽  
The Standard Model ◽  
Large Enhancement

We consider the effect of new physics on the branching ratio of Bs → l+l-γ where l = e, μ. If the new physics is of the form scalar/pseudoscalar, then it makes no contribution to Bs → l+l-γ, unlike in the case of Bs → l+l-, where it can potentially make a very large contribution. If the new physics is in the form of vector/axial-vector operators, then the present data on B → (K, K*) l+l- does not allow a large enhancement for B(Bs → l+l- γ). If the new physics is in the form of tensor/pseudotensor operators, then the data on B → (K, K*) l+l- gives no useful constraint but the data on B → K* γ does. Here again, a large enhancement of B(Bs → l+l-γ), much beyond the Standard Model expectation, is not possible. Hence, we conclude that the present data on b → s transitions allow a large boost in B(Bs → l+l-) but not in B(Bs → l+l-γ).

scholarly journals A note on gauge anomaly cancellation in effective field theories

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Ferruccio Feruglio
Keyword(s):  
Effective Field Theories ◽  
Effective Field ◽  
Field Theories ◽  
Anomaly Cancellation ◽  
Charge Assignment ◽  
The Standard Model ◽  
Renormalizable Theory ◽  
Complete Set ◽  
Gauge Anomalies ◽  
Gauge Anomaly

Abstract The conditions for the absence of gauge anomalies in effective field theories (EFT) are rivisited. General results from the cohomology of the BRST operator do not prevent potential anomalies arising from the non-renormalizable sector, when the gauge group is not semi-simple, like in the Standard Model EFT (SMEFT). By considering a simple explicit model that mimics the SMEFT properties, we compute the anomaly in the regularized theory, including a complete set of dimension six operators. We show that the dependence of the anomaly on the non-renormalizable part can be removed by adding a local counterterm to the theory. As a result the condition for gauge anomaly cancellation is completely controlled by the charge assignment of the fermion sector, as in the renormalizable theory.

scholarly journals Non-Relativistic Model for the Semileptonic Λb→Λc Decay

1997 ◽  
Vol 12 (03) ◽  
pp. 195-204 ◽  
Author(s):  
Debrupa Chakraverty ◽  
Triptesh De ◽  
Binayak Dutta-Roy ◽  
K. S. Gupta
Keyword(s):  
Heavy Quark ◽  
Decay Width ◽  
Branching Ratio ◽  
Relativistic Model ◽  
Heavy Quark Symmetry ◽  
Heavy Baryons

We calculate the decay width for [Formula: see text] in the framework of a non-relativistic quark (NRQ) model of heavy baryons where the light quarks play the role of spectators. Our calculation does not make an explicit use of the heavy quark symmetry. The branching ratio for the above process as calculated here agrees reasonably well with the experimental value.

The sircular polarization of γ-quanta in the radiative decay H Þ`ffγ (II)

2021 ◽  
pp. 134-141
Author(s):  
S.K. Abdullayev ◽  
◽  
E.Sh. Omarova ◽  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Circular Polarization ◽  
Invariant Mass ◽  
Decay Width ◽  
Radiative Decay ◽  
W Boson ◽  
Decay Channel ◽  
Fermion Pair ◽  
The Standard Model

Within the framework of the Standard Model, the radiative decay channel of the Higgs boson into fermion-antifermion pair is investigated: H Þ` ff γ. Taking into account the fermion and W -boson loop diagrams an analytical expression for the decay width is obtained, the circular polarization of the γ-quanta is studied in dependence of the angle θ and invariant mass of the fermion pair.

scholarly journals Cross Section Prediction for Inclusive Production of Z Boson in pp Collisions at s=14 TeV: A Study of Systematic Uncertainty due to Scale Dependence

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Hasan Ogul ◽  
Kamuran Dilsiz
Keyword(s):  
Cross Section ◽  
Production Cross Section ◽  
Z Boson ◽  
Production Cross ◽  
Branching Ratio ◽  
Leading Order ◽  
Proton Proton ◽  
Proton Collisions ◽  
Central Values ◽  
Proton Proton Collisions

Prediction of Z→l+l- production cross section (where l±=e±,μ±) in proton-proton collisions at s=14 TeV is estimated up to next-to-next-to-leading order (NNLO) in perturbative QCD including next-to-leading order (NLO) electroweak (EW) corrections. The total inclusive Z boson production cross section times leptonic branching ratio, within the invariant mass window 66<mll<116 GeV, is predicted using NNLO HERAPDF2.0 at NNLO QCD and NLO EW as σZTot=2111.69-26.92+26.31 (PDF) ±11 (αs) ±17 (scale) -30.98+57.41 (parameterization and model). Theoretical prediction of the fiducial cross section is further computed with the latest modern PDF models (CT14, MMHT2014, NNPDF3.0, HERAPDF2.0, and ABM12) at NNLO for QCD and NLO for EW. The central values of the predictions are based on DYNNLO 1.5 program and the uncertainties are extracted using FEWZ 3.1 program. In addition, the cross section is also calculated as functions of μR and μF scales. The choice of μR and μF for scale variation uncertainty is further discussed in detail.

scholarly journals Axial vector Z′ and anomaly cancellation

2017 ◽  
Vol 918 ◽  
pp. 220-244 ◽  
Author(s):  
Ahmed Ismail ◽  
Wai-Yee Keung ◽  
Kuo-Hsing Tsao ◽  
James Unwin
Keyword(s):  
Axial Vector ◽  
Anomaly Cancellation

Upper Bounds on Top Quark Mass, Z Boson Decay Widths and Mass Ratio M W / M Z

1992 ◽  
Vol 18 (4) ◽  
pp. 427-434
Author(s):  
Zhen-Jun Xiao ◽  
Gong-Ru Lu ◽  
Yi-bing DING
Keyword(s):  
Top Quark ◽  
Z Boson ◽  
Quark Mass ◽  
Upper Bounds ◽  
Mass Ratio ◽  
Top Quark Mass ◽  
Decay Widths

Analytic Calculations of the Branching Ratio and CP Violation in Bs0 → Ds+Ds− Decay

2020 ◽  
Vol 35 (15) ◽  
pp. 2050122
Author(s):  
H. R. Khan ◽  
E. H. Raslan ◽  
R. A. Reem
Keyword(s):  
Cp Violation ◽  
Decay Width ◽  
Branching Ratio ◽  
Gluon Condensate ◽  
Analytic Calculation ◽  
Experimental Measurements ◽  
Meson Decays ◽  
First Order ◽  
Theoretical Predictions ◽  
Charge Parity

We present an analytic calculation of Branching Ratio (BR) and Charge-Parity (CP) violating asymmetries of the [Formula: see text] meson decays to [Formula: see text] by calculating the amplitude and the decay width of the process including the chiral loop and gluon condensate to first-order. We find the BR of [Formula: see text] which is in agreement with other experimental measurements and theoretical predictions. We also calculate the direct CP violation, CP violation in mixing and CP violation due to interference which are [Formula: see text], [Formula: see text] and [Formula: see text], respectively.

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