9 research outputs found
New developments in PHOKHARA Monte Carlo generator
The present status of the physics program, which led to the development of
the Monte Carlo event generator PHOKHARA is described. The possibility of using
the radiative return method in various aspects of hadronic physics, from the
measurement of the hadronic cross section, to detailed investigations of the
hadronic dynamics is emphasized. New results are presented showing how to
measure baryon form factors using the knowledge of their spin in
baryon-antibaryon production with subsequent decay.Comment: Late
Radiative return physics program within EURIDICE network
A short review of both theoretical and experimental aspects of the radiative
return method is presented with the emphasize on the results obtained within
the EURIDICE network. It is shown that the method gives not only possibility of
an independent from the scan method measurement of the hadronic cross section,
but also can provide information concerning details of the hadronic
interactions.Comment: Presented by H. Czyz at The Final EURIDICE Meeting "Effective
theories of colours and flavours: from EURODAPHNE to EURIDICE", Kazimierz,
Poland, 24-27 August, 2006, minor linquistic change
FSR at leading and next-to-leading order in the radiative return at meson factories
The impact of final-state radiation (FSR) on the radiative return method for
the extraction of the e+e- hadronic cross section is discussed in detail.
Possible experimental tests of the model dependence of FSR are proposed for the
pi+pi- hadronic final state. The importance of the (pi+pi-photon) final state
contribution to the muon anomalous magnetic moment is investigated, and a
method based on the radiative return is proposed to extract these contributions
from data.Comment: Presented by H. Czyz at XXVII International Conference of Theoretical
Physics, `Matter To The Deepest', Ustron, 15-21 September 2003, Poland. To
appear in Acta Physica Polonica B: http://th-www.if.uj.edu.pl/act
The radiative return at phi- and B-factories: small-angle photon emission at next to leading order
The radiative return offers the unique possibility for a measurement of the
cross section of electron--positron annihilation into hadrons over a wide range
of energies. The large luminosity of present phi- and B-factories easily
compensates for the additional factor of alpha due to the emission of a hard
photon. Final states with photons at large angles can be easily identified. The
rate for events with collinear photons, however, is enhanced by a large
logarithm and allows, in particular at lower energies, for a complementary
measurement.
The Monte Carlo generator PHOKHARA, which includes next to leading order
corrections from virtual and real photon emission, has been extended from large
photon angles into the collinear region, using recent results for the virtual
corrections. In addition, the present version includes final state radiation
for muon and pion pair production and final states with four pions.
Implications for the experimental analysis at three typical energies, 1.02, 4
and 10.6 GeV, are presented: the magnitude of these new corrections is studied,
possibilities for the separation of initial and final state radiation are
proposed, and the differences with respect to the previous treatment based on
structure functions are investigated.Comment: 13 pages, 25 figures. Misprint in Eq.(24) correcte
Perspectives from the radiative return at meson factories
The measurement of the pion form factor and, more generally, of the cross section for electron-positron annihilation into hadrons through the radiative return has become an important task for high luminosity colliders such as the Phi- or B-meson factories. This quantity is crucial for predictions of the hadronic contributions to the anomalous magnetic moment of the muon, and to the running of the electromagnetic coupling. But the radiative return opens the possibility of many other physical applications. The physics potential of this method at high luminosity meson factories is discussed, the last upgraded version of the event generator PHOKHARA is presented, and future developments are highlighted