Precision measurement of the neutral pion lifetime.

Larin, I; Zhang, Y; Gasparian, A; Gan, L; Miskimen, R; Khandaker, M; Dale, D; Danagoulian, S; Pasyuk, E; Gao, H; Ahmidouch, A; Ambrozewicz, P; Baturin, V; Burkert, V; Clinton, E; Deur, A; Dolgolenko, A; Dutta, D; Fedotov, G; Feng, J; Gevorkyan, S; Glamazdin, A; Guo, L; Isupov, E; Ito, M M; Klein, F; Kowalski, S; Kubarovsky, A; Kubarovsky, V; Lawrence, D; Lu, H; Ma, L; Matveev, V; Morrison, B; Micherdzinska, A; Nakagawa, I; Park, K; Pedroni, R; Phelps, W; Protopopescu, D; Rimal, D; Romanov, D; Salgado, C; Shahinyan, A; Sober, D; Stepanyan, S; Tarasov, V V; Taylor, S; Vasiliev, A; Wood, M

Larin, I; Zhang, Y; Gasparian, A; Gan, L; Miskimen, R; Khandaker, M; Dale, D; Danagoulian, S; Pasyuk, E; Gao, H; Ahmidouch, A; Ambrozewicz, P; Baturin, V; Burkert, V; Clinton, E; Deur, A; Dolgolenko, A; Dutta, D; Fedotov, G; Feng, J; Gevorkyan, S; Glamazdin, A; Guo, L; Isupov, E; Ito, M M; Klein, F; Kowalski, S; Kubarovsky, A; Kubarovsky, V; Lawrence, D; Lu, H; Ma, L; Matveev, V; Morrison, B; Micherdzinska, A; Nakagawa, I; Park, K; Pedroni, R; Phelps, W; Protopopescu, D; Rimal, D; Romanov, D; Salgado, C; Shahinyan, A; Sober, D; Stepanyan, S; Tarasov, V V; Taylor, S; Vasiliev, A; Wood, M.

Afiliación

Larin I; Alikhanov Institute for Theoretical and Experimental Physics, National Research Center (NRC) "Kurchatov Institute," Moscow, 117218, Russia.
Zhang Y; Department of Physics, University of Massachusetts, Amherst, MA 01003, USA.
Gasparian A; Department of Physics, Duke University, Durham, NC 27708, USA.
Gan L; Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA.
Miskimen R; Department of Physics, North Carolina A&T State University, Greensboro, NC 27411, USA. gasparan@jlab.org.
Khandaker M; Department of Physics and Physical Oceanography, University of North Carolina Wilmington, Wilmington, NC 28403, USA.
Dale D; Department of Physics, University of Massachusetts, Amherst, MA 01003, USA.
Danagoulian S; Department of Physics, Norfolk State University, Norfolk, VA 23504, USA.
Pasyuk E; Department of Physics and Nuclear Engineering, Idaho State University, Pocatello, ID 83209, USA.
Gao H; Department of Physics, North Carolina A&T State University, Greensboro, NC 27411, USA.
Ahmidouch A; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.
Ambrozewicz P; Department of Physics, Duke University, Durham, NC 27708, USA.
Baturin V; Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA.
Burkert V; Department of Physics, North Carolina A&T State University, Greensboro, NC 27411, USA.
Clinton E; Department of Physics, North Carolina A&T State University, Greensboro, NC 27411, USA.
Deur A; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.
Dolgolenko A; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.
Dutta D; Department of Physics, University of Massachusetts, Amherst, MA 01003, USA.
Fedotov G; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.
Feng J; Alikhanov Institute for Theoretical and Experimental Physics, National Research Center (NRC) "Kurchatov Institute," Moscow, 117218, Russia.
Gevorkyan S; Department of Physics and Astronomy, Mississippi State University, Mississippi State, MS 39762, USA.
Glamazdin A; Department of Physics, Moscow State University, Moscow 119991, Russia.
Guo L; B. P. Konstantinov Petersburg Nuclear Physics Institute, NRC "Kurchatov Institute," Gatchina, St. Petersburg, 188300, Russia.
Isupov E; Department of Physics and Physical Oceanography, University of North Carolina Wilmington, Wilmington, NC 28403, USA.
Ito MM; Joint Institute for Nuclear Research, Dubna, 141980, Russia.
Klein F; Kharkov Institute of Physics and Technology, Kharkov, 310108, Ukraine.
Kowalski S; Department of Physics, Florida International University, Miami, FL 33199, USA.
Kubarovsky A; Department of Physics, Moscow State University, Moscow 119991, Russia.
Kubarovsky V; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.
Lawrence D; Department of Physics, The Catholic University of America, Washington, DC 20064, USA.
Lu H; Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Ma L; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.
Matveev V; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.
Morrison B; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.
Micherdzinska A; Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Nakagawa I; School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, China.
Park K; Alikhanov Institute for Theoretical and Experimental Physics, National Research Center (NRC) "Kurchatov Institute," Moscow, 117218, Russia.
Pedroni R; Department of Physics, Arizona State University, Tempe, AZ 85281, USA.
Phelps W; Department of Physics, George Washington University, Washington, DC 20064, USA.
Protopopescu D; RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan.
Rimal D; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.
Romanov D; Department of Physics, North Carolina A&T State University, Greensboro, NC 27411, USA.
Salgado C; Department of Physics, Computer Science and Engineering, Christopher Newport University, Newport News, VA 23606, USA.
Shahinyan A; School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK.
Sober D; Department of Physics, Florida International University, Miami, FL 33199, USA.
Stepanyan S; Department of Physics, Moscow Engineering Physics Institute, Moscow, Russia.
Tarasov VV; Department of Physics, Norfolk State University, Norfolk, VA 23504, USA.
Taylor S; Yerevan Physics Institute, Yerevan 0036, Armenia.
Vasiliev A; Department of Physics, The Catholic University of America, Washington, DC 20064, USA.
Wood M; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.

Science ; 368(6490): 506-509, 2020 05 01.

Article en En | MEDLINE | ID: mdl-32355026

ABSTRACT

ABSTRACT

The explicit breaking of the axial symmetry by quantum fluctuations gives rise to the so-called axial anomaly. This phenomenon is solely responsible for the decay of the neutral pion π0 into two photons (Î³Î³), leading to its unusually short lifetime. We precisely measured the decay width Γ of the [Formula see text] process. The differential cross sections for π0 photoproduction at forward angles were measured on two targets, carbon-12 and silicon-28, yielding [Formula see text], where stat. denotes the statistical uncertainty and syst. the systematic uncertainty. We combined the results of this and an earlier experiment to generate a weighted average of [Formula see text] Our final result has a total uncertainty of 1.50% and confirms the prediction based on the chiral anomaly in quantum chromodynamics.

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Texto completo: 1 Bases de datos: MEDLINE Idioma: En Revista: Science Año: 2020 Tipo del documento: Article País de afiliación: Rusia