Related papers: Hadronic shift in pionic hydrogen
In the recent years the NA49 experiment has collected data on Pb+Pb collisions at beam energies between 20 to 158 AGeV with the objective to cover the critical region of energy densities where the expected phase transition to a deconfined…
The average transverse momentum dependence on multiplicity shows in many experiments at center of mass energies ranging from 22 to 7000 GeV a slope change at a charged particle rapidity density constant within systematic uncertainties. We…
The Lamb shift (2P_{1/2}-2S_{1/2}) in the muonic helium ion (mu ^4_2He)^+ is calculated with the account of contributions of orders alpha^3, alpha^4, alpha^5 and alpha^6. Special attention is given to corrections of the electron vacuum…
Light, beyond-the-standard-model particles $X$ in the 1-100 MeV mass range can be produced in nuclear and hadronic reactions but would have to decay electromagnetically. We show that simple and well-understood low-energy hadronic processes…
We calculate the density shift and broadening of selected dipole transition lines of pionic helium in gaseous helium at low temperatures up to T=12 K and pressure up to a few bar. In the approximation of binary collisions the shift and…
Hadron multiplicities of $\pim$, $\pip$, $\km$ and $\kp$ have been measured in the deep-inelastic scattering of 27.5 GeV positrons off a hydrogen target. The data used in this analysis have been collected during the 2000 HERA running…
The recent PSI Lamb shift experiment and the controversy about proton size revived the interest in measuring the hyperfine splitting in muonic hydrogen as an alternative possibility for comparing ordinary and muonic hydrogen spectroscopy…
Rapidity-odd directed flow($v_1$) measurements for charged pions, protons and antiprotons near mid-rapidity ($y=0$) are reported in $\sqrt{s_{NN}} =$ 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV Au + Au collisions as recorded by the STAR…
We report the first direct measurement of the hyperfine transition of the ground state positronium. The hyperfine structure between ortho-positronium and para-positronium is about 203 GHz. We develop a new optical system to accumulate about…
In the fixed energy environment of the $e^{+}e^{-}$ collider DA$\Phi$NE, KLOE can measure the cross section of the process $e^{+}e^{-} \to$ hadrons as a function of the hadronic system energy using the radiative return. At energies below 1…
From the partial wave analysis, the phase shift D33 of pion nucleon scattering containing the D(1232) resonance, corresponding to isospin I=3/2 and angular momentum J=3/2, has been parameterized over the energy range 1100 < W < 1375 MeV,…
The proton structure and proton polarizability corrections to the Lamb shift of electronic hydrogen and muonic hydrogen were evaluated on the basis of modern experimental data on deep inelastic structure functions. Numerical value of proton…
We analyze the photon rates from a hadronic gas in equilibrium using chiral reduction formulas and a density expansion. The chiral reduction is carried to second order in the pion density which in principal includes all kinetic processes of…
Frequency shifts of the ^199Hg^+ 5d^10 6s ^2S_1/2 (F=0, M_F=0) to 5d^9 6s^2 ^2D_5/2 (F=2, M_F=0) electric-quadrupole transition at 282 nm due to external fields are calculated, based on a combination of measured atomic parameters and ab…
Recently it has been demonstrated that particle factories, such as DAPHNE and PEP-II, operating at fixed center-of-mass energies, are able to measure hadronic cross sections as a function of the hadronic system energy using the raditive…
We have developed a field theory formalism to calculate $in$-$medium$ properties of hadrons within a unified approach that exploits a single Lagrangian to describe simultaneously both matter background and meson fluctuations. In this paper…
Recent measurements of the proton to pion ratio at $\sqrt{s}_{NN}=2.7$ TeV by the ALICE collaboration at the LHC have found it to be lower than predictions from thermal fits. In this paper we investigate the role that the extended mass…
The ITEP-PNPI collaboration presents the results of the measurements of the spin rotation parameter A in the elastic scattering of positive and negative pions on protons at P_beam = 1.62 GeV/c. The setup included a longitudinally-polarized…
An unusual but effective way to determine at threshold the dpi -> NN transition strength is to exploit the hadronic ground-state broadening in pionic deuterium, accessible by x-ray spectroscopy. The broadening is dominated by the true…
The results of calculations of the muon transfer rate from the 1S state of muonic hydrogen to the nucleus of a free oxygen atom are presented in the interval of collision energies from 10^(-4) to 10 eV. The calculations were performed…