M. Münch

Effective pion mass in the nuclear medium deduced from deeply bound pionic states in 207Pb

Abstract Deeply bound 1s states of π − as well as the 2p states in 207 Pb were identified in the 208 Pb(d, 3 He) reaction at 600 MeV. The binding energies of π − in 207 Pb have been determined as B π (2 p )=5.31±0.09 MeV and B π (1 s )=7.1±0.2 MeV by comparing the observed Q -value spectrum with theory. These values indicate that the effective π − mass increases by 19.3±2.7 MeV at the center of the 207 Pb nucleus.

Experimental indication of a reduced chiral order parameter from the 1s π− state in 205Pb

Abstract The isovector potential parameter ( b 1 ) of the s -wave pion–nucleus interaction was deduced to be b 1 =−0.116 +0.015 −0.017 m π −1 by using the binding energy and width of the recently observed deeply bound 1 s π − state in 205 Pb combined with the known 1 s states of light pionic atoms. An enhancement of b 1 over the free- πN value (|−0.090|) is indicated, which may infer that the chiral order parameter (squared pion decay constant, f π 2 ) is reduced by a factor of 0.78 +0.13 −0.09 in the nuclear medium of 205 Pb where the bound π − is located. The isoscalar part is accounted for as arising mainly from a double-scattering effect, without invoking a large density-quadratic term.

Study of exclusive one-pion and one-eta production using hadron and dielectron channels in pp reactions at kinetic beam energies of 1.25 GeV and 2.2 GeV with HADES

Abstract.We present measurements of exclusive

Independent measurement of the Hoyle state β feeding from B 12 using Gammasphere

\ensuremath \pi^{+,0}

Decay studies of N ≈ Z nuclei from 75 Sr to 102 Sn

and

Dilepton analysis in the HADES spectrometer for C+C at 2 A GeV

\eta

DILEPTON ANALYSIS IN THE HADES SPECTROMETER FOR 12C+12C AT 2 AGEV

production in pp reactions at 1.25GeV and 2.2GeV beam kinetic energy in hadron and dielectron channels. In the case of

Deeply bound 1s and 2p pionic states in 205Pb and effective pion mass in nuclear matter

\pi^{+}_{}

Decay studies of

and

\mth{N\approx Z}

\pi^{0}_{}