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Physical Review D

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Diquark resonance and single top production at the Large Hadron Collider

Durmus Karabacak^*, S. Nandi^†, and Santosh Kumar Rai^‡

Department of Physics and Oklahoma Center for High Energy Physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA

^*durmas@ostatemail.okstate.edu
^†s.nandi@okstate.edu
^‡santosh.rai@okstate.edu

Phys. Rev. D 85, 075011 – Published 12 April, 2012

DOI: https://doi.org/10.1103/PhysRevD.85.075011

Abstract

New physics at the TeV scale is highly anticipated at the LHC. New particles with color, if within the LHC energy reach, will be copiously produced. One such particle is a diquark, having the quantum numbers of two quarks, and can be either a scalar or a vector. It will decay to two light quarks, or two top quarks, or a top and a light quark, (up-type or down-type depending on the quantum number of the produced diquark). If singly produced, it can be looked for as a dijet resonance, or as giving extra contribution to the single top production or $t t$ production. In this work, we consider a color-sextet vector diquark having the quantum number of $(u d)$ -type, its resonance production, and the subsequent decay to $t b$ , giving rise to excess contribution to the single top production. Even though the diquark mass is large, its strong resonance production dominates the weak production of $t b$ for a wide range of the diquark mass. Also, its subsequent decay to $t b$ produces a very hard $b$ jet compared to the usual electroweak production. In addition, the missing energy in the final state event is much larger from the massive diquark decays. Thus, with suitable cuts, the final state with $b$ , $\bar{b}$ and a charged lepton together with large missing energy stands out compared to the standard model background. We perform a detailed study of both the signal and the background. We find that such a diquark is accessible at the 7 TeV LHC up to a mass of about 3.3 TeV with the luminosity $1 {fb}^{- 1}$ , while the reach goes up to about 4.3 TeV with a luminosity of $10 {fb}^{- 1}$ .

Article Text

References (45)

R. Barbier et al., Phys. Rep. 420, 1 (2005).
J. L. Hewett and T. G. Rizzo, Phys. Rep. 183, 193 (1989).
A. De Rujula, L. Maiani, and R. Petronzio, Phys. Lett. 140B, 253 (1984).
J. H. Kuhn and P. M. Zerwas, Phys. Lett. 147B, 189 (1984).
U. Baur, I. Hinchliffe, and D. Zeppenfeld, Int. J. Mod. Phys. A 2, 1285 (1987).
U. Baur, M. Spira, and P. M. Zerwas, Phys. Rev. D 42, 815 (1990).
P. H. Frampton and S. L. Glashow, Phys. Lett. B 190, 157 (1987).
S. P. Martin, Phys. Rev. D 46, 2197 (1992).
J. Bagger, C. Schmidt, and S. King, Phys. Rev. D 37, 1188 (1988).
C. T. Hill, Phys. Lett. B 266, 419 (1991).
C. T. Hill and S. J. Parke, Phys. Rev. D 49, 4454 (1994).
D. A. Dicus, B. Dutta, and S. Nandi, Phys. Rev. D 51, 6085 (1995).
D. A. Dicus, C. Kao, S. Nandi, and J. Sayre, Phys. Rev. D 83, 091702 (2011); J. Sayre, D. A. Dicus, C. Kao, and S. Nandi, 84, 015011 (2011).
K. S. Babu, R. N. Mohapatra, and S. Nasri, Phys. Rev. Lett. 98, 161301 (2007).
J. C. Pati and A. Salam, Phys. Rev. D 10, 275 (1974); 11, 703(E) (1975).
R. N. Mohapatra and R. E. Marshak, Phys. Rev. Lett. 44, 1316 (1980); 44, 1644 (1980).
Z. Chacko and R. N. Mohapatra, Phys. Rev. D 59, 055004 (1999).
B. A. Dobrescu, K. Kong, and R. Mahbubani, Phys. Lett. B 670, 119 (2008).
C. T. Hill and E. H. Simmons, Phys. Rep. 381, 235 (2003); 390, 553(E) (2004).
G. Aad et al. (ATLAS Collaboration), Phys. Rev. Lett. 105, 161801 (2010).
V. Khachatryan et al. (CMS Collaboration), Phys. Rev. Lett. 105, 211801 (2010).
G. Aad et al. (ATLAS Collaboration), Phys. Lett. B 708, 37 (2012).
S. Chatrchyan et al. (CMS Collaboration), Phys. Lett. B 704, 123 (2011).
S. Atag, O. Cakir, and S. Sultansoy, Phys. Rev. D 59, 015008 (1998).
E. Arik, O. Cakir, S. A. Cetin, and S. Sultansoy, J. High Energy Phys. 09 (2002) 024.
O. Cakir and M. Sahin, Phys. Rev. D 72, 115011 (2005).
R. N. Mohapatra, N. Okada, and H. B. Yu, Phys. Rev. D 77, 011701 (2008).
E. L. Berger, Q. H. Cao, C. R. Chen, G. Shaughnessy, and H. Zhang, Phys. Rev. Lett. 105, 181802 (2010).
T. Han, I. Lewis, and Z. Liu, J. High Energy Phys. 12 (2010) 085.
G. F. Giudice, B. Gripaios, and R. Sundrum, J. High Energy Phys. 08 (2011) 055.
P. Richardson and D. Winn, Eur. Phys. J. C 72, 1862 (2012).
V. Barger, T. Han, and D. G. E. Walker, Phys. Rev. Lett. 100, 031801 (2008).
R. Frederix and F. Maltoni, J. High Energy Phys. 01 (2009) 047.
H. Zhang, E. L. Berger, Q. H. Cao, C. R. Chen, and G. Shaughnessy, Phys. Lett. B 696, 68 (2011).
N. Kosnik, I. Dorsner, J. Drobnak, S. Fajfer, and J. F. Kamenik, Proc. Sci., EPS-HEP2011 (2011) 380.
I. Gogoladze, Y. Mimura, N. Okada, and Q. Shafi, Phys. Lett. B 686, 233 (2010).
N. Kidonakis, Phys. Rev. D 83, 091503 (2011).
N. Kidonakis, Phys. Rev. D 81, 054028 (2010).
N. Kidonakis, Phys. Rev. D 82, 054018 (2010).
J. Pumplin, D. R. Stump, J. Huston, H. L. Lai, P. M. Nadolsky, and W. K. Tung, J. High Energy Phys. 07 (2002) 012.
ATLAS Collaboration, Report No. ATLAS-CONF-2011-118, 2011.
J. Alwall, M. Herquet, F. Maltoni, O. Mattelaer, and T. Stelzer, J. High Energy Phys. 06 (2011) 128.
G. L. Bayatian et al. (CMS Collaboration), Report No. CERN-LHCC-2006-001, and Report No. CMS-TDR-008-1 (2006).
M. Arai, K. Huitu, S. K. Rai, and K. Rao, J. High Energy Phys. 08 (2010) 082.
K. Huitu, S. K. Rai, K. Rao, S. D. Rindani, and P. Sharma, J. High Energy Phys. 04 (2011) 026.