Related papers: Four-pion production
We present a novel framework for analyzing four-body semileptonic weak decays, performing the first high-twist analysis of the $D_s \to \left[ \pi\pi \right]_{\rm S}$ form factors using light-cone distribution amplitudes for the isoscalar…
QCD-based scaling arguments predict the predominance of longitudinal over transverse electroproduction of pions by terms $\propto Q^2$. However, data from JLAB, Cornell and DESY, covering a wide kinematical range $1 < Q^2 < 11\, {\rm…
The OKA Collaboration has obtained a new upper limit on the $K^+ \to \pi^0\pi^0\pi^0 e^+ \nu$ decay probability which is 65 times lower than the one currently listed by PDG. However it is still about $10^{4}$ times worse than the…
A recently suggested high-energy Born-form representation of the one-loop helicity amplitudes for e^+e^- to W^+W^- is supplemented by including W^+- decay and hard-photon radiation. Results for the differential and the total cross section…
We study, at leading order in the large number of colours expansion and within the Resonance Chiral Theory framework, the odd-intrinsic-parity $e^+ e^- \rightarrow \pi^+ \pi^- (\pi^0, \eta)$ cross-sections in the energy regime populated by…
We study transitions between Upsilon states with the emission of charged pions using 477 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. We select inclusive Upsilon(4S) -> mu+ mu- pi+ pi- X…
We have considered the holographic large $N_c$ QCD model proposed by Sakai and Sugimoto and evaluated the non-Abelian DBI-action on the D8-brane upto $(\alpha')^4$ terms. Restricting to the pion sector, these corrections give rise to four…
We consider exclusive multi-peripheral production of four charged pions in proton-proton collisions at high energies with simultaneous exchange of three pomerons/reggeons. The amplitude(s) for the genuine $2 \to 6$ process are written in…
The branching ratios and CP asymmetries of $B\to \pi\pi$ decays measured in B factory experiments indicate a large ratio of color-suppressed ($C$) to color-allowed ($T$) tree contributions and a large relative phase between the tree and…
Recently the BaBar Collaboration published new data on the cross section for the annihilation e+e- -> phi pi0, obtained using the initial state radiation technique at a center of mass energy of 10.6 GeV. Such a process represents an…
The doubly differential cross sections for the $^4$He$(\pi^+,\pi^-) 4p$ reaction were calculated using both a two-nucleon sequential single charge exchange model and an intranuclear cascade code. Final state interactions between the two…
Cross sections of the e+e- annihilation into one photon plus two vector mesons, such as J/psi rho, J/psi phi, and rho phi at the center of mass energy \sqrt{s}=10.58GeV are calculated. These shed light on the measurement of the e+e-…
We report on a detailed investigation of four-body $p p \to p p \pi^+ \pi^-$ and $p \bar{p} \to p \bar{p} \pi^+ \pi^-$) reactions which constitute an irreducible background to three-body processes $p p \to p p M$, where $M$ is a broad…
tau -> (3 pions) nu_tau decays are analysed within the framework of the resonance effective theory of QCD. We work out the relevant Lagrangian that describes the axial-vector current hadronization contributing to these processes, in…
We address the problem of pion production in low energy $\pi$-nucleus collisions. For the production mechanism we assume a simple model consisting of a coherent sum of single pion exchange and the excitation---followed by the decay into two…
Production of electroweak bosons in e+e- annihilation into quarks and into leptons at energies much greater than 100 Gev is considered. We account for double-logarithmic contributions to all orders in electroweak couplings. It is assumed…
We study the hard exclusive production of two pions in the virtual photon fragmentation region with various invariant masses including the resonance region. The amplitude is expressed in terms of two-pion light cone distribution amplitudes…
We calculate the branching ratio of the non-resonant $B \to D^- \pi^+\pi^+\pi^- $ decay using a simple model based on the framework of the factorization approach. In naive factorization approach, there are only tow tree diagrams for this…
Pion electroproduction off the proton is analyzed in a new framework based on a general parametrization of transition amplitudes, including constraints from gauge invariance and threshold behavior. Data with energies $1.13~{\rm…
The complete one-loop QED initial state, final state and initial--final state interference corrections to the process e+e- -> pi+pi- are presented. Analytic formulae are given for the virtual and for the real photon corrections. The total…