Minimal fourfamily supergravity model
Abstract
We investigate minimal fourfamily MSSM supergravity theories containing an additional general ({ital t}{prime},{ital b}{prime},{tau}{prime},{nu}{prime}) of heavy fermions along with their superpartners. We constrain the models by demanding gauge coupling constant unification at high energy scales, perturbative values for all Yukawa couplings for energy scales up to the grandunification scale, radiative electroweak (EW) symmetry breaking via renormalization group evolution down from the grandunification scale, a neutral LSP, and consistency with constraints from direct searches for new particles and precision electroweak data. The perturbative constraints imply a rather light fourthfamily quark and lepton spectrum, and tan {beta}{approx_lt}3. The lightest {ital CP}even Higgs boson mass receives fourthfamily loop corrections that can result in as much as a 30% increase over the corresponding threefamily mass value. Significant fourthfamily Yukawa coupling contributions to the evolution of scalar masses lead to unexpected mass hierarchies among the sparticles. The {tilde {tau}} {sub 1}{sup {prime}} is generally the lightest slepton and the lightest squark is the {tilde {ital b}} {sub 1}{sup {prime}}. A significant lower bound is placed on the gluino mass by the simple requirement that the {tilde {tau}} {sub 1}{sup {prime}} not be the LSP. Sleptons of the first two families are much more massive comparedmore »
 Authors:

 Davis Institute for High Energy Physics, Department of Physics, U.C. Davis, Davis, California 95616 (United States)
 University of Kansas, Department of Physics and Astronomy, Lawrence, Kansas 66045 (United States)
 Publication Date:
 Research Org.:
 University of California
 OSTI Identifier:
 282787
 DOE Contract Number:
 FG0391ER40674; FG0285ER40214
 Resource Type:
 Journal Article
 Journal Name:
 Physical Review, D
 Additional Journal Information:
 Journal Volume: 53; Journal Issue: 3; Other Information: PBD: Feb 1996
 Country of Publication:
 United States
 Language:
 English
 Subject:
 66 PHYSICS; SUPERGRAVITY; FERMIONS; SPARTICLES; COUPLING CONSTANTS; YUKAWA POTENTIAL; QUARKS; LEPTONS; HIGGS BOSONS; CORRECTIONS; SPECTRA; RENORMALIZATION GROUP METHOD
Citation Formats
Gunion, J F, McKay, D W, and Pois, H. Minimal fourfamily supergravity model. United States: N. p., 1996.
Web. doi:10.1103/PhysRevD.53.1616.
Gunion, J F, McKay, D W, & Pois, H. Minimal fourfamily supergravity model. United States. https://doi.org/10.1103/PhysRevD.53.1616
Gunion, J F, McKay, D W, and Pois, H. Thu .
"Minimal fourfamily supergravity model". United States. https://doi.org/10.1103/PhysRevD.53.1616.
@article{osti_282787,
title = {Minimal fourfamily supergravity model},
author = {Gunion, J F and McKay, D W and Pois, H},
abstractNote = {We investigate minimal fourfamily MSSM supergravity theories containing an additional general ({ital t}{prime},{ital b}{prime},{tau}{prime},{nu}{prime}) of heavy fermions along with their superpartners. We constrain the models by demanding gauge coupling constant unification at high energy scales, perturbative values for all Yukawa couplings for energy scales up to the grandunification scale, radiative electroweak (EW) symmetry breaking via renormalization group evolution down from the grandunification scale, a neutral LSP, and consistency with constraints from direct searches for new particles and precision electroweak data. The perturbative constraints imply a rather light fourthfamily quark and lepton spectrum, and tan {beta}{approx_lt}3. The lightest {ital CP}even Higgs boson mass receives fourthfamily loop corrections that can result in as much as a 30% increase over the corresponding threefamily mass value. Significant fourthfamily Yukawa coupling contributions to the evolution of scalar masses lead to unexpected mass hierarchies among the sparticles. The {tilde {tau}} {sub 1}{sup {prime}} is generally the lightest slepton and the lightest squark is the {tilde {ital b}} {sub 1}{sup {prime}}. A significant lower bound is placed on the gluino mass by the simple requirement that the {tilde {tau}} {sub 1}{sup {prime}} not be the LSP. Sleptons of the first two families are much more massive compared to the LSP and other neutralinos and charginos than in the threefamily models; in particular, all sleptons belonging to the first three families could easily lie beyond the reach of a {radical}{ital s} =500 GeV {ital e}{sup +}{ital e}{sup {minus}} collider. Consistency tests of the RG equations via mass sum rules and relations are explored. Relations between slepton masses and gaugino masses are shown to be very sensitive to the presence of a fourth generation. The most important nearfuture experimental probes of the fourfamily models are reviewed.},
doi = {10.1103/PhysRevD.53.1616},
url = {https://www.osti.gov/biblio/282787},
journal = {Physical Review, D},
number = 3,
volume = 53,
place = {United States},
year = {1996},
month = {2}
}