نتایج جستجو برای: ππ stacking
تعداد نتایج: 15427 فیلتر نتایج به سال:
The all–important consequence of Chiral Dynamics for ππ scattering is the Adler zero, which forces ππ amplitudes to grow asymptotically. The continuation of this subthreshold zero into the physical regions requires a P –wave resonance, to be identified with the ρ. It is a feature of ππ scattering that convergent dispersive integrals for the I = 1 channel are essentially saturated by the ρ–reson...
We explore the decay of a vector meson to two pseudoscalar mesons on the lattice with N f = 2 flavours of sea quark. Although we are working with quark masses that do not allow a physical decay, we show how the transition rate can be evaluated from the amplitude for ρ → ππ and from the annihilation component of ππ → ππ. We explore the decay amplitude for two different pion momenta and find cons...
I calculate the leading logarithmic contributions up to two-loop order of the octet part of the K0 → ππ amplitude. This sector of the weak chiral Lagrangian is believed to be the main source of the enhancement of the I = 0 relative to the I = 2 K0 → ππ amplitude, the so-called ∆I = 1/2 rule. I discuss the procedure of chiral extrapolations of lattice data specific to K → ππ decays and study the...
We present a method of determining the CKM-angle α by performing simultaneous measurements of the mixing-induced CP asymmetries of the decays Bd → ππ and Bd → KK̄. The accuracy of our approach is limited by SU(3)-breaking effects originating from b̄ → d̄ss̄ QCD-penguin diagrams. Using plausible power-counting arguments we show that these uncertainties are expected to be of the same order as those a...
The phases of terms of amplitude that arise from the ππ interaction are obtained by using a simple realistic model of ππ interaction via virtual ρ-meson, instead of the ChPT. It is shown that the standard ChPT approach cannot reproduce the contribution of the ρ-meson to the ππ interaction. It is shown that the interference between the terms of amplitude with different CP-parity appears only whe...
Using data collected by the high energy photoproduction experiment FOCUS at Fermilab we study the doubly and singly Cabibbo suppressed decays D and D s → K ππ. Our measurements of Γ(D → Kππ)/Γ(D → Kππ) = 0.0065 ± 0.0008 ± 0.0004 and Γ(D s → K ππ)/ Γ(D s → K Kπ) = 0.127 ± 0.007± 0.014 are based on samples of 189± 24 D and 567± 31 D s reconstructed events, respectively. We also present Dalitz plo...
The reversal of aromaticity and antiaromaticity upon excitation to the lowest ππ* state impacts on photophysics photoreactivity various annulenes. This unifying principle can guide rationalization a plethora excited-state reactions has strong predictive power in design new photochemical transformations. For more details, see Review by H. Ottosson et al. (DOI: 10.1002/chem.202203748)
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