Research output: Contribution to journal › Article › peer-review
Measurement of the running of the fine structure constant below 1 GeV with the KLOE detector. / Anastasi, A.; Babusci, D.; Bencivenni, G. et al.
In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol. 767, 10.04.2017, p. 485-492.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Measurement of the running of the fine structure constant below 1 GeV with the KLOE detector
AU - Anastasi, A.
AU - Babusci, D.
AU - Bencivenni, G.
AU - Berlowski, M.
AU - Bloise, C.
AU - Bossi, F.
AU - Branchini, P.
AU - Budano, A.
AU - Caldeira Balkeståhl, L.
AU - Cao, B.
AU - Ceradini, F.
AU - Ciambrone, P.
AU - Curciarello, F.
AU - Czerwiński, E.
AU - D'Agostini, G.
AU - Dané, E.
AU - De Leo, V.
AU - De Lucia, E.
AU - De Santis, A.
AU - De Simone, P.
AU - Di Cicco, A.
AU - Di Domenico, A.
AU - Di Salvo, R.
AU - Domenici, D.
AU - D'Uffizi, A.
AU - Fantini, A.
AU - Felici, G.
AU - Fiore, S.
AU - Gajos, A.
AU - Gauzzi, P.
AU - Giardina, G.
AU - Giovannella, S.
AU - Graziani, E.
AU - Happacher, F.
AU - Heijkenskjöld, L.
AU - Johansson, T.
AU - Kamińska, D.
AU - Krzemien, W.
AU - Kupsc, A.
AU - Loffredo, S.
AU - Lukin, P. A.
AU - Mandaglio, G.
AU - Martini, M.
AU - Mascolo, M.
AU - Messi, R.
AU - Miscetti, S.
AU - Morello, G.
AU - Moricciani, D.
AU - Moskal, P.
AU - Papenbrock, M.
AU - The KLOE-2 Collaboration
N1 - Publisher Copyright: © 2016 The Author
PY - 2017/4/10
Y1 - 2017/4/10
N2 - We have measured the running of the effective QED coupling constant α(s) in the time-like region 0.6+e−→μ+μ−γ. It represents the first measurement of the running of α(s) in this energy region. Our results show a more than 5σ significance of the hadronic contribution to the running of α(s), which is the strongest direct evidence both in time- and space-like regions achieved in a single measurement. By using the e+e−→π+π− cross section measured by KLOE, the real and imaginary parts of the shift Δα(s) have been extracted. From a fit of the real part of Δα(s) and assuming the lepton universality the branching ratio BR(ω→μ+μ−)=(6.6±1.4stat±1.7syst)⋅10−5 has been determined.
AB - We have measured the running of the effective QED coupling constant α(s) in the time-like region 0.6+e−→μ+μ−γ. It represents the first measurement of the running of α(s) in this energy region. Our results show a more than 5σ significance of the hadronic contribution to the running of α(s), which is the strongest direct evidence both in time- and space-like regions achieved in a single measurement. By using the e+e−→π+π− cross section measured by KLOE, the real and imaginary parts of the shift Δα(s) have been extracted. From a fit of the real part of Δα(s) and assuming the lepton universality the branching ratio BR(ω→μ+μ−)=(6.6±1.4stat±1.7syst)⋅10−5 has been determined.
KW - Vacuum polarization
KW - α running
KW - LUMINOSITY
KW - MUON PAIR PRODUCTION
KW - HADRONIC CROSS-SECTION
KW - FSR
KW - ANGLE BHABHA SCATTERING
KW - VACUUM POLARIZATION
KW - RADIATIVE RETURN
KW - E(+)E(-)
KW - arunning
UR - http://www.scopus.com/inward/record.url?scp=85014040536&partnerID=8YFLogxK
U2 - 10.1016/j.physletb.2016.12.016
DO - 10.1016/j.physletb.2016.12.016
M3 - Article
VL - 767
SP - 485
EP - 492
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
SN - 0370-2693
ER -
ID: 9164961