Reach of Fermilab Tevatron upgrades in gauge-mediated supersymmetry breaking models

Howard Baer; P. G. Mercadante; Xerxes Tata; Yili Wang

doi:10.1103/PhysRevD.60.055001

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Reach of Fermilab Tevatron upgrades in gauge-mediated supersymmetry breaking models

Howard Baer¹, P. G. Mercadante², Xerxes Tata², and Yili Wang²

¹Department of Physics, Florida State University, Tallahassee, Florida 32306
²Department of Physics and Astronomy, University of Hawaii, Honolulu, Hawaii 96822

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Phys. Rev. D 60, 055001 – Published 14 July, 1999

DOI: https://doi.org/10.1103/PhysRevD.60.055001

Abstract

We examine signals for sparticle production at the Fermilab Tevatron within the framework of gauge-mediated supersymmetry breaking models for four different model lines, each of which leads to qualitatively different signatures. We identify cuts to enhance the signal above standard model backgrounds, and use ISAJET to evaluate the supersymmetry reach of experiments at the Fermilab Main Injector and at the proposed TeV33. For the model lines that we have examined, we find that the reach is at least as large, and frequently larger, than in the minimal supergravity framework. For two of these model lines, we find that the ability to identify b-quarks and $τ$ -leptons with high efficiency and purity is essential for the detection of the signal.

References (36)

M. Dine, W. Fischler, and M. Srednicki, Nucl. Phys. B189, 575 (1981); ibid.S. Dimopoulos and S. Raby, B192, 353 (1981); ibid.L. Alvarez-Guamé, M. Claudson, and M. Wise, B207, 96 (1982).
M. Dine and A. Nelson, Phys. Rev. D 48, 1277 (1993); ibid.M. Dine, A. Nelson, and Y. Shirman, 51, 1362 (1995); ibid.M. Dine, A. Nelson, Y. Nir, and Y. Shirman, 53, 2658 (1996).
S. Dimopoulos, M. Dine, S. Raby, and S. Thomas, Phys. Rev. Lett. 76, 3494 (1996); S. Dimopoulos, S. Thomas, and J. Wells, Phys. Rev. D 54, 3283 (1996); Nucl. Phys. B488, 39 (1997).
S. Ambrosanio et al., Phys. Rev. Lett. 76, 3498 (1996); S. AmbrosanioPhys. Rev. D 54, 5395 (1996).
K. S. Babu, C. Kolda, and F. Wilczek, Phys. Rev. Lett. 77, 3070 (1996).
H. Baer, M. Brhlik, C. H. Chen, and X. Tata, Phys. Rev. D 55, 4463 (1997).
J. Bagger, K. Matchev, and D. Pierce, Phys. Rev. D 55, 3188 (1997).
R. Rattazzi and U. Sarid, Nucl. Phys. B501, 297 (1997).
D. Dicus, B. Dutta, and S. Nandi, Phys. Rev. Lett. 78, 3055 (1997); Phys. Rev. D 56, 5748 (1997); ibid.K. Cheung, D. Dicus, B. Dutta, and S. Nandi, 58, 015008 (1998); B. Dutta, D. J. Mueller, and S. Nandi, Nucl. Phys. B544, 451 (1999); D. J. Mueller and S. Nandi, Phys. Rev. D 60, 015008 (1999).
C. H. Chen and J. F. Gunion, Phys. Lett. B 420, 77 (1998); Phys. Rev. D 58, 075005 (1998).
J. Feng and T. Moroi, Phys. Rev. D 58, 035001 (1998).
E. Gabrielli and U. Sarid, Phys. Rev. D 58, 115003 (1998).
H. Baer, P. G. Mercadante, X. Tata, and Y. Wang, Phys. Lett. B 435, 109 (1998).
S. Martin and J. Wells, Phys. Rev. D 59, 035008 (1999).
See G. Giudice and R. Rattazzi, hep-ph/9801271, 1998 for a review.
For a review of the MSUGRA model, see H. P. Nilles, Phys. Rep. 110, 1 (1984); R. Arnowitt and P. Nath, Lectures presented at the VII J. A. Swieca Summer School, Campos do Jordao, Brazil, 1993, Report No. CTP-TAMU-52/93.
S. Martin, Phys. Rev. D 55, 3177 (1997).
N. Deshpande, B. Dutta, and S. Oh, Phys. Rev. D 56, 519 (1997).
M. S. Alam et al., Phys. Rev. Lett. 74, 2885 (1995); R. Barate et al., Phys. Lett. B 429, 169 (1998).
ALEPH Collaboration, R. Barate et al., Phys. Lett. B 429, 201 (1998); DELPHI Collaboration report at the LEP Experiments Committee Meeting, CERN, 1998; see also, P. Abreu et al., Eur. Phys. J. C 7, 595 (1999); L3 Collaboration, M. Acciari et al., Phys. Lett. B 444, 503 (1998).
The limit $m_{W_{1}} ≳ 150 GeV$ from a non-observation [30][31] of an excess in diphoton $+ E_{T}$ events at the Tevatron translates to a bound $m_{Z_{1}} ≳ 72 GeV$ and independently excludes a slightly smaller region of the plane.
L3 Collaboration report at the LEP Experiments Committee Meeting, CERN, 1998. See also reports of other collaborations.
We are grateful to Graham Kribs, Steve Martin and Jim Wells for bringing this to our attention.
H. Baer, F. Paige, S. Protopopescu, and X. Tata, hep-ph/9810440, 1998.
S. Ambrosanio, S. Martin, and G. Kribs, Nucl. Phys. B516, 55 (1998).
In addition to these decays, ISAJET also includes several other three body decays of $l_{2} ≃ l_{L}, {\tilde{τ}}_{2}$ and ${\tilde{ν}}_{l}, {\tilde{ν}}_{τ}$ in various approximations. These decays are unimportant for us because the heavier sleptons generally have two-body decays, but might be important in models [28] where these are light. The reader who uses ISAJET in models where these decays are important is advised to become aware of the various approximations under which these are calculated.
S. Dimopoulos, Thomas, and Wells, Ref. [3].
This is not special to GMSB models. It could happen in models with additional D-terms which invert the customary hierarchy between left- and right- sleptons. See, e.g., J. Amundson et al., in New Directions for High Energy Physics, Snowmass, CO, 1996, edited by D. Cassel, L. Trindle Gennari and R. Siemann; A. de Gouvea, A. Friedland, and H. Murayama, Phys. Rev. D 59, 095008 (1999); for examples of such terms in the SUGRA framework (where the inversion is easier than in the GMSB model, since sleptons start out with universal masses).
These model lines were first proposed for study at the run II SUSY and Higgs Workshop held at Fermilab in 1998. The nomenclature used is different from that in the Workshop.
B. Abbott et al., Phys. Rev. Lett. 80, 442 (1998).
F. Abe et al., Phys. Rev. Lett. 81, 1791 (1998); F. AbePhys. Rev. D 59, 092002 (1999).
Although the chargino pair production cross section is an order of magnitude larger than the slepton cross section, it should be remembered that the branching fraction for both charginos to decay to e or to $μ$ is just $\sim 2 %$ .
Admittedly, we have not attempted to separate slepton events from other SUSY sources. These additional SUSY sources dominate for $Λ <~ 90 GeV$ for which $Z_{2} \to l l_{1}$ is kinematically accessible and has a large branching ratio. Lepton pairs from neutralino decays will necessarily have $m (ll) <~ m_{Z_{2}} \sqrt{1 - m_{l_{1}}^{2} {/ m}_{Z_{2}}^{2}} \sqrt{1 - m_{Z_{1}}^{2} {/ m}_{l_{1}}^{2}}$ , while those from slepton pair production form a continuum, possibly extending beyond this.
We have checked that this additional requirement causes essentially no loss of signal.
We studied several other distributions including, jet multiplicity, $θ_{bb},$ $δ φ (bb)$ , but none of these proved useful to enhance the signal over the top background.
M. Hohlmann, Report No. Fermilab-Conf-96/330-E, 1996.

[c1] M. Dine, W. Fischler, and M. Srednicki, Nucl. Phys. B189, 575 (1981); ibid.S. Dimopoulos and S. Raby, B192, 353 (1981); ibid.L. Alvarez-Guamé, M. Claudson, and M. Wise, B207, 96 (1982).

[c2] M. Dine and A. Nelson, Phys. Rev. D 48, 1277 (1993); ibid.M. Dine, A. Nelson, and Y. Shirman, 51, 1362 (1995); ibid.M. Dine, A. Nelson, Y. Nir, and Y. Shirman, 53, 2658 (1996).

[c3] S. Dimopoulos, M. Dine, S. Raby, and S. Thomas, Phys. Rev. Lett. 76, 3494 (1996); S. Dimopoulos, S. Thomas, and J. Wells, Phys. Rev. D 54, 3283 (1996); Nucl. Phys. B488, 39 (1997).

[c4] S. Ambrosanio et al., Phys. Rev. Lett. 76, 3498 (1996); S. AmbrosanioPhys. Rev. D 54, 5395 (1996).

[c5] K. S. Babu, C. Kolda, and F. Wilczek, Phys. Rev. Lett. 77, 3070 (1996).

[c6] H. Baer, M. Brhlik, C. H. Chen, and X. Tata, Phys. Rev. D 55, 4463 (1997).

[c7] J. Bagger, K. Matchev, and D. Pierce, Phys. Rev. D 55, 3188 (1997).

[c8] R. Rattazzi and U. Sarid, Nucl. Phys. B501, 297 (1997).

[c9] D. Dicus, B. Dutta, and S. Nandi, Phys. Rev. Lett. 78, 3055 (1997); Phys. Rev. D 56, 5748 (1997); ibid.K. Cheung, D. Dicus, B. Dutta, and S. Nandi, 58, 015008 (1998); B. Dutta, D. J. Mueller, and S. Nandi, Nucl. Phys. B544, 451 (1999); D. J. Mueller and S. Nandi, Phys. Rev. D 60, 015008 (1999).

[c10] C. H. Chen and J. F. Gunion, Phys. Lett. B 420, 77 (1998); Phys. Rev. D 58, 075005 (1998).

[c11] J. Feng and T. Moroi, Phys. Rev. D 58, 035001 (1998).

[c12] E. Gabrielli and U. Sarid, Phys. Rev. D 58, 115003 (1998).

[c13] H. Baer, P. G. Mercadante, X. Tata, and Y. Wang, Phys. Lett. B 435, 109 (1998).

[c14] S. Martin and J. Wells, Phys. Rev. D 59, 035008 (1999).

[c15] See G. Giudice and R. Rattazzi, hep-ph/9801271, 1998 for a review.

[c16] For a review of the MSUGRA model, see H. P. Nilles, Phys. Rep. 110, 1 (1984); R. Arnowitt and P. Nath, Lectures presented at the VII J. A. Swieca Summer School, Campos do Jordao, Brazil, 1993, Report No. CTP-TAMU-52/93.

[c17] S. Martin, Phys. Rev. D 55, 3177 (1997).

[c18] N. Deshpande, B. Dutta, and S. Oh, Phys. Rev. D 56, 519 (1997).

[c19] M. S. Alam et al., Phys. Rev. Lett. 74, 2885 (1995); R. Barate et al., Phys. Lett. B 429, 169 (1998).

[c20] ALEPH Collaboration, R. Barate et al., Phys. Lett. B 429, 201 (1998); DELPHI Collaboration report at the LEP Experiments Committee Meeting, CERN, 1998; see also, P. Abreu et al., Eur. Phys. J. C 7, 595 (1999); L3 Collaboration, M. Acciari et al., Phys. Lett. B 444, 503 (1998).

[c21] The limit $m_{W_{1}} ≳ 150 GeV$ from a non-observation [30][31] of an excess in diphoton $+ E_{T}$ events at the Tevatron translates to a bound $m_{Z_{1}} ≳ 72 GeV$ and independently excludes a slightly smaller region of the plane.

[c22] L3 Collaboration report at the LEP Experiments Committee Meeting, CERN, 1998. See also reports of other collaborations.

[c23] We are grateful to Graham Kribs, Steve Martin and Jim Wells for bringing this to our attention.

[c24] H. Baer, F. Paige, S. Protopopescu, and X. Tata, hep-ph/9810440, 1998.

[c25] S. Ambrosanio, S. Martin, and G. Kribs, Nucl. Phys. B516, 55 (1998).

[c26] In addition to these decays, ISAJET also includes several other three body decays of $l_{2} ≃ l_{L}, {\tilde{τ}}_{2}$ and ${\tilde{ν}}_{l}, {\tilde{ν}}_{τ}$ in various approximations. These decays are unimportant for us because the heavier sleptons generally have two-body decays, but might be important in models [28] where these are light. The reader who uses ISAJET in models where these decays are important is advised to become aware of the various approximations under which these are calculated.

[c27] S. Dimopoulos, Thomas, and Wells, Ref. [3].

[c28] This is not special to GMSB models. It could happen in models with additional D-terms which invert the customary hierarchy between left- and right- sleptons. See, e.g., J. Amundson et al., in New Directions for High Energy Physics, Snowmass, CO, 1996, edited by D. Cassel, L. Trindle Gennari and R. Siemann; A. de Gouvea, A. Friedland, and H. Murayama, Phys. Rev. D 59, 095008 (1999); for examples of such terms in the SUGRA framework (where the inversion is easier than in the GMSB model, since sleptons start out with universal masses).

[c29] These model lines were first proposed for study at the run II SUSY and Higgs Workshop held at Fermilab in 1998. The nomenclature used is different from that in the Workshop.

[c30] B. Abbott et al., Phys. Rev. Lett. 80, 442 (1998).

[c31] F. Abe et al., Phys. Rev. Lett. 81, 1791 (1998); F. AbePhys. Rev. D 59, 092002 (1999).

[c32] Although the chargino pair production cross section is an order of magnitude larger than the slepton cross section, it should be remembered that the branching fraction for both charginos to decay to e or to $μ$ is just $\sim 2 %$ .

[c33] Admittedly, we have not attempted to separate slepton events from other SUSY sources. These additional SUSY sources dominate for $Λ <~ 90 GeV$ for which $Z_{2} \to l l_{1}$ is kinematically accessible and has a large branching ratio. Lepton pairs from neutralino decays will necessarily have $m (ll) <~ m_{Z_{2}} \sqrt{1 - m_{l_{1}}^{2} {/ m}_{Z_{2}}^{2}} \sqrt{1 - m_{Z_{1}}^{2} {/ m}_{l_{1}}^{2}}$ , while those from slepton pair production form a continuum, possibly extending beyond this.

[c34] We have checked that this additional requirement causes essentially no loss of signal.

[c35] We studied several other distributions including, jet multiplicity, $θ_{bb},$ $δ φ (bb)$ , but none of these proved useful to enhance the signal over the top background.

[c36] M. Hohlmann, Report No. Fermilab-Conf-96/330-E, 1996.

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Reach of Fermilab Tevatron upgrades in gauge-mediated supersymmetry breaking models

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