ε′/ε Results from KTeV
نویسنده
چکیده
Since the 1964 discovery of KL → π+π− [1], understanding CP violation has been a major goal of particle physics. Subsequent experiments showed that the dominant mechanism of CP violation in neutral kaons (still the only particle system in which CP violation has been observed) is a small asymmetry between K0 → K and K → K0 mixing. This asymmetry, referred to as indirect CP violation, results in the KL and KS being states of mixed CP. The parameter ε, which is used to parameterize this effect, quantifies the CP impurity of the KL and KS states: KS ∼ Keven + εKodd (1) KL ∼ Kodd + εKeven, (2)
منابع مشابه
ar X iv : h ep - p h / 99 06 37 4 v 1 1 5 Ju n 19 99 BA - 99 - 44 SUPERSYMMETRIC CP VIOLATION ε ′ / ε DUE TO ASYMMETRIC A - MATRIX
We study contributions of supersymmetric CP phases to the CP violation ε/ε in models with asymmetric A-matrices. We consider asymmetric Amatrices, which are obtained from string-inspired supergravity. We show that a certain type of asymmetry of A-matrices enhances supersymmetric contributions to the CP violation ε/ε and the supersymmetric contribution to ε/ε can be of order of the KTeV result, ...
متن کاملThe precise determination of ℜe (ε ′ /ε)
CP violation in the neutral kaon system is known to be dominated by the mixing of K 0 and K 0. Direct CP violation in the 2 pion decays of neutral kaons has been a controversial subject over the last decade. A strong experimental effort has been devoted to the precise measurement of the direct CP violation parameter ℜe (ε ′ /ε). After 10 years of detector development, data collection and analys...
متن کاملStandard Model Confronting New Results for ε ′ / ε
We analyze the CP violating ratio ε/ε in the Standard Model in view of the new KTeV results. We review the present status of the most important non-perturbative parameters B (1/2) 6 , B (3/2) 8 , B̂K and of the strange quark mass ms. We also briefly discuss the issues of final state interactions and renormalization scheme dependence. Updating the values of the CKM parameters, of mt and Λ (4) MS ...
متن کاملTheoretical status of ε ′ / ε
The present theoretical status of the parameter for direct CP violation ε/ε in the Standard Model is reviewed and compared with most recent experimental measurements of the same quantity. After collecting the basic expressions for ε/ε, the situation of hadronic matrix element calculations is summarised. The matrix elements constitute the dominant source of uncertainty for theoretical determinat...
متن کاملMeasurement of Direct Cp Violation by the Na48 Experiment at Cern
CP violation occurs in the Standard Model through the imaginary phase in the CKM mixing matrix. An alternative mechanism, proposed shortly after the discovery of the effect, is a superweak interaction. The latter can be ruled out by experimental observation of direct CP violation, parametrized by ε. Theoretical calculations of ε within the Standard Model are hard, but most predictions give ε/ε ...
متن کاملDirect CP , T and / or CPT violations in the K 0 − K 0 system - Implications of the recent KTeV results on 2 π decays - Yoshihiro Takeuchi
The recent results on the CP violating parameters Re(ε/ε) and ∆φ ≡ φ00 − φ+− reported by the KTeV Collaboration are analyzed with a view to constrain CP , T and CPT violations in a decay process. Combining with some relevant data compiled by the Particle Data Group, we find Re(ε2− ε0) = (0.85±3.11)×10−4 and Im(ε2− ε0) = (3.2±0.7)×10−4, where Re(εI) and Im(εI) represent respectively CP/CPT and C...
متن کامل