TAU LEPTON HADRONIC DECAYS AT BABAR AND BELLE

2013 ◽  
Vol 28 (24) ◽  
pp. 1360007
Author(s):  
G. D. LAFFERTY
Keyword(s):  
Quark Mass ◽  
Branching Fractions ◽  
Mass Difference ◽  
Total Sample ◽  
Tau Lepton ◽  
Hadronic Decays ◽  
Decay Modes ◽  
Systematic Uncertainties ◽  
Lepton Decays ◽  
Lower Limits

The BaBar and Belle experiments together recorded a total sample of some 3 ×109 tau lepton decays between the years 2000 and 2010. This enabled many new and improved measurements of tau hadronic decays to be made, and resulted in lower limits for branching fractions to rare and forbidden hadronic modes, such as those mediated by second-class weak currents which are sensitive to the u–d quark mass difference. Better measurements of strange decays have contributed to more precise data on the CKM matrix element, |Vus|. However, only limited progress has been made in measurements that feed into knowledge of the value of the strong coupling constant, αs, and the strange quark mass. This is largely due to the dominance of systematic uncertainties on branching fractions and shapes of mass spectra (spectral functions) for some of the important hadronic tau decay modes.

scholarly journals MEASUREMENT OF THE η → π+π-π0 DECAY WITH WASA-at-COSY DETECTOR

2011 ◽  
Vol 26 (03n04) ◽  
pp. 622-624
Author(s):  
◽  
PATRIK ADLARSON ◽  
MARCIN ZIELIŃSKI
Keyword(s):  
Dalitz Plot ◽  
Quark Mass ◽  
Mass Difference ◽  
Current Status ◽  
Hadronic Decays ◽  
Density Population ◽  
Physics Programme ◽  
Made In

One of the objectives of the physics programme of the WASA-at-COSY facility is to study the isospin violating η hadronic decays into π+π-π0 systems driven by the term of QCD Lagrangian which depends on the d and u quark mass difference. These studies can be made in terms of the Dalitz plot parameters describing the density population which is proportional to the square of the amplitude |A(x, y)|2. This contribution describes the current status of the analysis of the η → π+π-π0 decay in the pd →3 Heη and as well in the pp → ppη reaction with WASA-at-COSY.

scholarly journals Strange-Quark Mass from Tau-Lepton Decays withO(αs3)Accuracy

2005 ◽  
Vol 95 (1) ◽  
Author(s):  
P. A. Baikov ◽  
K. G. Chetyrkin ◽  
J. H. Kühn
Keyword(s):  
Quark Mass ◽  
Strange Quark ◽  
Tau Lepton ◽  
Strange Quark Mass ◽  
Lepton Decays

scholarly journals D MESON HADRONIC DECAYS AT CLEO-c

2011 ◽  
Vol 26 (19) ◽  
pp. 3121-3170 ◽  
Author(s):  
FAN YANG
Keyword(s):  
Rare Decay ◽  
Branching Fractions ◽  
D Meson ◽  
Hadronic Decays ◽  
Decay Modes ◽  
Wide Range ◽  
The Absolute ◽  
Cabibbo Suppressed

The recent CLEO-c results on hadronic decays of D and Ds mesons are presented. First the absolute branching fractions for D and Ds mesons using a double tag technique are discussed, then are the Cabibbo suppressed decays and doubly Cabibbo suppressed decays. Finally, I present the inclusive and rare decay modes and other measurements from CLEO-c. These decays illuminate a wide range of physics. A brief theoretical introduction is given before the corresponding discussion on measurement.

Water, Water, Here and There

2018 ◽  
Author(s):  
Steven E. Vigdor
Keyword(s):  
Quark Mass ◽  
Mass Difference ◽  
Baryon Number ◽  
Electroweak Phase Transition ◽  
Hydrogen Burning ◽  
Quark Masses ◽  
Grand Unified Theories ◽  
Down Quark ◽  
Unified Theories ◽  
The Stability

Chapter 4 deals with the stability of the proton, hence of hydrogen, and how to reconcile that stability with the baryon number nonconservation (or baryon conservation) needed to establish a matter–antimatter imbalance in the infant universe. Sakharov’s three conditions for establishing a matter–antimatter imbalance are presented. Grand unified theories and experimental searches for proton decay are described. The concept of spontaneous symmetry breaking is introduced in describing the electroweak phase transition in the infant universe. That transition is treated as the potential site for introducing the imbalance between quarks and antiquarks, via either baryogenesis or leptogenesis models. The up–down quark mass difference is presented as essential for providing the stability of hydrogen and of the deuteron, which serves as a crucial stepping stone in stellar hydrogen-burning reactions that generate the energy and elements needed for life. Constraints on quark masses from lattice QCD calculations and violations of chiral symmetry are discussed.

Experimental upper limits on branching fractions for unexpected decay modes of theτlepton

1982 ◽  
Vol 25 (11) ◽  
pp. 2869-2886 ◽  
Author(s):  
K. G. Hayes ◽  
M. L. Perl ◽  
M. S. Alam ◽  
A. M. Boyarski ◽  
M. Breidenbach ◽  
...  
Keyword(s):  
Branching Fractions ◽  
Decay Modes ◽  
Upper Limits

scholarly journals Optimising top-quark threshold scan at CLIC using genetic algorithm

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
K. Nowak ◽  
A.F. Żarnecki
Keyword(s):  
Genetic Algorithm ◽  
Pair Production ◽  
Top Quark ◽  
Quark Mass ◽  
Mass Measurement ◽  
Production Cross ◽  
Model Parameters ◽  
Top Quark Mass ◽  
Systematic Uncertainties ◽  
Pair Production Cross Section

Abstract One of the important goals at the future e+e− colliders is to measure the top-quark mass and width in a scan of the pair production threshold. However, the shape of the pair-production cross section at the threshold depends also on other model parameters, as the top Yukawa coupling, and the measurement is a subject to many systematic uncertainties. Presented in this work is the study of the top-quark mass determination from the threshold scan at CLIC. The most general approach is used with all relevant model parameters and selected systematic uncertainties included in the fit procedure. Expected constraints from other measurements are also taken into account. It is demonstrated that the top-quark mass can be extracted with precision of the order of 30 to 40 MeV, including considered systematic uncertainties, already for 100 fb−1 of data collected at the threshold. Additional improvement is possible, if the running scenario is optimised. With the optimisation procedure based on the genetic algorithm the statistical uncertainty of the mass measurement can be reduced by about 20%. Influence of the collider luminosity spectra on the expected precision of the measurement is also studied.

SUBSTRUCTURE EFFECT ON ρ-ω MIXING IN CHARGE-SYMMETRY VIOLATION

1992 ◽  
Vol 07 (32) ◽  
pp. 3037-3043 ◽  
Author(s):  
T. GOLDMAN ◽  
J.A. HENDERSON ◽  
A.W. THOMAS
Keyword(s):  
Symmetry Breaking ◽  
Quark Model ◽  
Quark Mass ◽  
Mass Shell ◽  
Mass Difference ◽  
Charge Symmetry Breaking ◽  
Symmetry Violation ◽  
Charge Symmetry ◽  
A Charge ◽  
Simple Quark Model

In generating a charge-symmetry breaking potential using ρ-ω mixing it is usually assumed that the mixing amplitude is constant (at the on-mass-shell value). Since the exchanged meson is actually far off-shell one must question the validity of this assumption. By constructing a simple quark model in which the mixing is generated by the u-d quark mass difference, we find that the assumption seems to be a very poor one.

Recent Belle results on the hadronic decays of tau lepton

2010 ◽  
Vol 198 (1) ◽  
pp. 157-164 ◽  
Author(s):  
H. Hayashii ◽  
M. Fujikawa
Keyword(s):  
Tau Lepton ◽  
Hadronic Decays

scholarly journals Study of nonleptonic B(s)∗→ M1M2 (M = D,Ds,π,K) weak decays with factorization approach

2015 ◽  
Vol 30 (27) ◽  
pp. 1550162 ◽  
Author(s):  
Qin Chang ◽  
Pan-Pan Li ◽  
Xiao-Hui Hu ◽  
Lin Han
Keyword(s):  
Flavor Physics ◽  
Branching Fractions ◽  
Form Factors ◽  
Approximation Formula ◽  
Heavy Flavor ◽  
Transition Form ◽  
Factorization Approach ◽  
Decay Modes ◽  
Weak Decays ◽  
Belle Ii

Motivated by the experiments of heavy flavor physics at running LHC and upgrading SuperKEKB/Belle-II in the future, the nonleptonic [Formula: see text] [Formula: see text] weak decays are studied in this paper. The amplitudes are calculated with factorization approach, and the transition form factors [Formula: see text] are evaluated within BSW model. With the reasonable approximation [Formula: see text], our predictions of branching fractions are presented. Numerically, the CKM-favored tree-dominated [Formula: see text] and [Formula: see text] decays have the largest branching fractions of the order [Formula: see text], and hence will be firstly observed by forthcoming Belle-II experiment. However, most of the other decay modes have the branching fractions [Formula: see text] and thus are hardly to be observed soon. Besides, for the possible detectable [Formula: see text] decays with branching fractions [Formula: see text], some useful ratios, such as [Formula: see text], etc. are presented and discussed in detail.

scholarly journals Non-standard interactions in $\tau^- \to (\pi^-\eta,\pi^-\pi^0)\nu_{\tau}$ decays

2019 ◽  
Author(s):  
Gabriel Lopez Castro
Keyword(s):  
Weak Interactions ◽  
High Energy ◽  
New Physics ◽  
Tau Lepton ◽  
Tau Decays ◽  
Set Constraints ◽  
Belle Ii ◽  
Lepton Decays ◽  
Energy Processes ◽  
New Interactions

Originally thought as clean processes to study the hadronization of the weak currents, semileptonic tau lepton decays can be useful to set constraints on non-standard (NS) weak interactions. We study the effects of new interactions in \tau^- \to (\pi^-\eta,\pi^-\pi^0)\nu_{\tau}τ−→(π−η,π−π0)ντ decays and find that they are sensitive probes of these New Physics effects in the form of scalar and tensor interactions, respectively. Further improved measurements at Belle II will set limits on these scalar interactions that are similar to other low and high energy processes.

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