Abstract
This paper describes a topological search for an invisibly decaying Higgs boson, H, produced via the Bjorken process (e+e-→HZ). The analysis is based on data recorded using the OPAL detector at LEP at centre-of-mass energies from 183 to 209 GeV corresponding to a total integrated luminosity of 629 pb-1. In the analysis only hadronic decays of the Z boson are considered. A scan over Higgs boson masses from 1 to 120 GeV and decay widths from 1 to 3000 GeV revealed no indication for a signal in the data. From a likelihood ratio of expected signal and standard model background we determine upper limits on cross-section times branching ratio to an invisible final state. For moderate Higgs boson decay widths, these range from about 0.07 pb (MH=60 GeV) to 0.57 pb (MH=114 GeV). For decay widths above 200 GeV the upper limits are of the order of 0.15 pb. The results can be interpreted in general scenarios predicting a large invisible decay width of the Higgs boson. As an example we interpret the results in the so-called stealthy Higgs scenario. The limits from this analysis exclude a large part of the parameter range of this scenario experimentally accessible at LEP 2.
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References
ALEPH Collaboration, R. Barate et al., Phys. Lett. B 565, 61 (2003)
LEP Higgs Working Group, hep-ex/0107032
G.F. Giudice, R. Rattazzi, J.D. Wells, Nucl. Phys. B 595, 250 (2001)
M. Battaglia, D. Dominici, J.F. Gunion, J.D. Wells, hep-ph/0402062
T. Binoth, J.J. van der Bij, Z. Phys. C 75, 17 (1997)
OPAL Collaboration, G. Abbiendi et al., Eur. Phys. J. C 27, 311 (2003)
J.J. van der Bij, hep-ph/0603082
T. Binoth, J.J. van der Bij, hep-ph/9908256
J.F. Gunion, H.E. Haber, G.L. Kane, S. Dawson, The Higgs Hunter’s Guide (Addison-Wesley, Reading, MA, 1990), p. 140
OPAL Collaboration, K. Ahmet et al., Nucl. Instrum. Methods A 305, 275 (1991)
S. Anderson et al., Nucl. Instrum. Methods A 403, 326 (1998)
G. Aguillon et al., Nucl. Instrum. Methods A 417, 266 (1998)
B.E. Anderson et al., IEEE Trans. Nucl. Sci. 41, 845 (1994)
OPAL Collaboration, K. Ackerstaff et al., Phys. Lett. B 391, 221 (1997)
OPAL Collaboration, G. Abbiendi et al., Eur. Phys. J. C 26, 479 (2003)
N. Brown, W.J. Stirling, Phys. Lett. B 252, 657 (1990)
G.D. Cowan, J. Phys. G 17, 1537 (1991)
S. Catani, Y.L. Dokshitzer, M. Olsson, G. Turnock, B.R. Webber, Phys. Lett. B 269, 432 (1991)
S. Bethke, Z. Kunszt, D.E. Soper, W.J. Stirling, Nucl. Phys. B 370, 310 (1992)
S. Bethke, Z. Kunszt, D.E. Soper, W.J. Stirling, Nucl. Phys. B 523, 681 (1998) [Erratum]
N. Brown, W.J. Stirling, Z. Phys. C 53, 629 (1992)
P. Janot, CERN 96-01, vol. 2, 309 (1996)
S. Jadach, B.F. Ward, Z. Was, Comput. Phys. Commun. 130, 260 (2000)
T. Sjöstrand, Comput. Phys. Commun. 82, 74 (1994)
T. Sjöstrand, LU TP 95-20
J. Fujimoto et al., Comput. Phys. Commun. 100, 128 (1997)
J. Fujimoto et al., CERN 96-01, vol. 2, 30 (1996)
E. Budinov et al., CERN 96-01, vol. 2, 216 (1996)
R. Engel, J. Ranft, Phys. Rev. D 54, 4244 (1996)
G. Marchesini et al., Comput. Phys. Commun. 67, 465 (1992)
J.A.M. Vermaseren, Nucl. Phys. B 229, 347 (1983)
OPAL Collaboration, J. Allison et al., Nucl. Instrum. Methods A 317, 47 (1992)
OPAL Collaboration, M.Z. Akrawy et al., Phys. Lett. B 253, 511 (1991)
OPAL Collaboration, G. Abbiendi et al., Phys. Lett. B 453, 138 (1999)
OPAL Collaboration, G. Abbiendi et al., Phys. Lett. B 476, 256 (2000)
OPAL Collaboration, G. Abbiendi et al., Eur. Phys. J. C 32, 303 (2003)
L3 Collaboration, M. Acciarri et al., Phys. Lett. B 485, 85 (2000)
OPAL Collaboration, G. Abbiendi et al., Eur. Phys. J. C 7, 407 (1999)
M.W. Grunewald et al., hep-ph/0005309
A.L. Read, J. Phys. G 28, 2693 (2002)
G. Abbiendi et al., OPAL Collaboration, Eur. Phys. J. C 40, 317 (2005)
T. Junk, Nucl. Instrum. Methods A 434, 435 (1999)
R.D. Cousins, V.L. Highland, Nucl. Instrum. Methods A 320, 331 (1992)
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Abbiendi, G., Ainsley, C., Åkesson, P. et al. Search for invisibly decaying Higgs bosons with large decay width using the OPAL detector at LEP. Eur. Phys. J. C 49, 457–472 (2007). https://doi.org/10.1140/epjc/s10052-006-0170-x
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DOI: https://doi.org/10.1140/epjc/s10052-006-0170-x