Abstract.
A new precise determination of the \( \eta\) meson mass is presented. It is based on a measurement of the threshold for the \( \gamma p\rightarrow p\eta\) reaction using the tagger focal-plane microscope detector at the MAMI-B facility in Mainz. The tagger microscope has a higher energy resolution than the standard tagging spectrometer and, hence, allowed an improvement in the accuracy compared to the previous \( \eta\) mass measurement at MAMI-B. Special emphasis was put on a very careful energy calibration of the electron beam and the tagging device, which reduced considerably the systematic uncertainty compared to the previous MAMI experiment. The result \( m_{\eta}=(547.865 \pm 0.031_{stat.}\pm 0.062_{syst.})\) MeV agrees very well with the precise values of the NA48, KLOE, CLEO and COSY-ANKE Collaborations and deviates by \( 6\sigma\) from the smaller value obtained by the GEM Collaboration at COSY.
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References
J. Beringer et al., Phys. Rev. D 86, 010001 (2012)
A. Duane et al., Phys. Rev. Lett. 32, 425 (1974)
F. Plouin et al., Phys. Lett. B 276, 526 (1992)
B. Krusche et al., Z. Phys. A 351, 237 (1995)
PDG Collaboration (D.E. Groom et al.), Eur. Phys. J. C 15, 1 (2000)
A. Lai et al., Phys. Lett. B 533, 196 (2002)
PDG Collaboration (S. Eidelman et al.), Phys. Lett. B 592, 1 (2004)
M. Abdel-Bary et al., Phys. Lett. B 619, 281 (2005)
F. Ambrosino et al., JHEP 12, 073 (2007)
D.H. Miller et al., Phys. Rev. Lett. 99, 122002 (2007)
P. Goslawski et al., Phys. Rev. D 85, 112011 (2012)
H. Herminghaus et al., Nucl. Instrum. Methods A 138, 1 (1976)
Th. Walcher, Prog. Part. Nucl. Phys. 24, 189 (1990)
M. Oreglia et al., Phys. Rev. D 25, 2259 (1982)
A. Starostin et al., Phys. Rev. C 64, 055205 (2001)
A. Reiter et al., Eur. Phys. J. A 30, 461 (2006)
A. Nikolaev, PhD Thesis, Rheinische Friedrich-Wilhelms-Universität Bonn (2011)
A. Jankowiak, Compilation of: Measurement of the electron beam energy at the Mainz Microtron, MAMI Internal Report 03/2006, Institut für Kernphysik, Mainz (2006)
A. Jankowiak, Eur. Phys. J. A 28, 149 (2006)
I. Anthony et al., Nucl. Instrum. Methods A 301, 230 (1991)
S.J. Hall et al., Nucl. Instrum. Methods A 368, 698 (1996)
D. Watts, Calorimetry in Particle Physics: Proceedings of the 11th International Conference, Perugia, Italy, 2004, edited by C. Cecchi, P. Lubrano, M. Pepe (World Scientific, Singapore, 2005) p. 560
R. Novotny, IEEE Trans. Nucl. Sc. 38, 392 (1991)
Th. Dörk, Diploma Thesis, Institut für Kernphysik, Johannes Gutenberg-Universität Mainz (1996)
W.-T. Chiang, S.N. Yang, L. Tiator, D. Drechsel, Nucl. Phys. A 700, 429 (2002)
B. Krusche et al., Phys. Rev. Lett. 74, 3736 (1995)
E. McNicoll et al., Phys. Rev. C 82, 035208 (2010)
S. Schumann et al., Eur. Phys. J. A 43, 269 (2010)
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The Crystal Ball at MAMI, TAPS and A2 Collaborations., Nikolaev, A., Aguar-Bartolomé, P. et al. Determination of the \( \eta\) mass with the Crystal Ball at MAMI-B. Eur. Phys. J. A 50, 58 (2014). https://doi.org/10.1140/epja/i2014-14058-1
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DOI: https://doi.org/10.1140/epja/i2014-14058-1