6533b821fe1ef96bd127c16c
RESEARCH PRODUCT
Neutron Skin ofPb208from Coherent Pion Photoproduction
M. UnverzagtA. KnezevicA. PolonskiR. F. B. CodlingA. StarostinC. M. TarbertS. SchadmandR.o. OwensK. LivingstonL. ZanaG. RosnerP. GrabmayrD. BranfordT. RostomyanH. J. ArendsD. P. WattsJ. C. McgeorgeE. J. DownieVolker MetagI. J. D. MacgregorV. S. BekrenevV. L. KashevarovM. LangE. HeidF. ZehrV. LisinW. J. BriscoeD. MekterovicP. AguarA. NikolaevO. JahnP. PedroniD. KrambrichD. M. ManleyM. KorolijaK FoehlJason BrudvikR. KondratievM. RostI. SupekS. CherepnyaS. SchumannR. W. NovotnyR. BeckJ. AhrensM. MartinezJ. W. PriceA. BraghieriR. GregorJ. R. M. AnnandB. M. K. NefkensD. I. GlazierD. HornidgeM. KotullaB. BoillatD. I. SoberTh. WalcherS. LugertS. N. PrakhovAndy ThomasB. Kruschesubject
PhysicsEquation of stateMeson010308 nuclear & particles physicsScatteringGeneral Physics and AstronomyRadius01 natural sciencesNuclear physicsPion0103 physical sciencesHigh Energy Physics::ExperimentNeutronNuclear Experiment010306 general physicsMicrotronCrystal Balldescription
Information on the size and shape of the neutron skin on (208)Pb is extracted from coherent pion photoproduction cross sections measured using the Crystal Ball detector together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections, the half-height radius and diffuseness of the neutron distribution are found to be c(n)=6.70±0.03(stat.) fm and a(n)=0.55±0.01(stat.)(-0.03)(+0.02)(sys.) fm, respectively, corresponding to a neutron skin thickness Δr(np)=0.15±0.03(stat.)(-0.03)(+0.01)(sys.) fm. The results give the first successful extraction of a neutron skin thickness with an electromagnetic probe and indicate that the skin of (208)Pb has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2014-06-18 | Physical Review Letters |