New physics from the top at the LHC Chien-Yi Chen Ayres Freitas Email author Tao Han Keith S. M. Lee Article

First Online: 21 November 2012 Received: 30 July 2012 Revised: 15 October 2012 Accepted: 20 October 2012 DOI :
10.1007/JHEP11(2012)124

Cite this article as: Chen, C., Freitas, A., Han, T. et al. J. High Energ. Phys. (2012) 2012: 124. doi:10.1007/JHEP11(2012)124 Abstract The top quark may hold the key to new physics associated with the electroweak symmetry-breaking sector, given its large mass and enhanced coupling to the Higgs sector. We systematically categorize generic interactions of a new particle that couples to the top quark and a neutral particle, which is assumed to be heavy and stable, thus serving as a candidate for cold dark matter. The experimental signatures for new physics involving top quarks and its partners at the Large Hadron Collider (LHC) may be distinctive, yet challenging to disentangle. We optimize the search strategy at the LHC for the decay of the new particle to a top quark plus missing energy and propose the study of its properties, such as its spin and couplings. We find that, at 14 TeV with an integrated luminosity of 100 fb^{−1} , a spin-zero top partner can be observed at the 5σ level for a mass of 675 GeV. A spin-zero particle can be differentiated from spin-1/2 and spin-1 particles at the 5σ level with a luminosity of 10 fb^{−1} .

Keywords Supersymmetry Phenomenology Phenomenology of Field Theories in Higher Dimensions

References [1]

J. Incandela and F. Gianotti,

Latest update in the search for the Higgs boson , talks at CERN LHC seminar, July 4 (2012),

http://indico.cern.ch/event/197461 .

[2]

G.F. Giudice,

Naturally Speaking: The Naturalness Criterion and Physics at the LHC ,

arXiv:0801.2562 [

INSPIRE ].

[3]

P. Meade and M. Reece,

Top partners at the LHC: Spin and mass measurement ,

Phys. Rev .

D 74 (2006) 015010 [

hep-ph/0601124 ] [

INSPIRE ].

ADS [4]

T. Han, R. Mahbubani, D.G. Walker and L.-T. Wang,

Top Quark Pair plus Large Missing Energy at the LHC ,

JHEP
05 (2009) 117 [

arXiv:0803.3820 ] [

INSPIRE ].

ADS CrossRef [5]

T. Plehn, M. Spannowsky, M. Takeuchi and D. Zerwas,

Stop Reconstruction with Tagged Tops ,

JHEP
10 (2010) 078 [

arXiv:1006.2833 ] [

INSPIRE ].

ADS CrossRef [6]

T. Plehn, M. Spannowsky and M. Takeuchi,

Boosted Semileptonic Tops in Stop Decays ,

JHEP
05 (2011) 135 [

arXiv:1102.0557 ] [

INSPIRE ].

ADS CrossRef [7]

Y. Bai, H.-C. Cheng, J. Gallicchio and J. Gu,

Stop the Top Background of the Stop Search ,

JHEP
07 (2012) 110 [

arXiv:1203.4813 ] [

INSPIRE ].

ADS CrossRef [8]

D.S. Alves, M.R. Buckley, P.J. Fox, J.D. Lykken and C.-T. Yu,

Stops and MET: The Shape of Things to Come ,

arXiv:1205.5805 [

INSPIRE ].

[9]

Z. Han, A. Katz, D. Krohn and M. Reece,

(Light) Stop Signs ,

JHEP
08 (2012) 083 [

arXiv:1205.5808 ] [

INSPIRE ].

ADS CrossRef [10]

D.E. Kaplan, K. Rehermann and D. Stolarski,

Searching for Direct Stop Production in Hadronic Top Data at the LHC ,

JHEP
07 (2012) 119 [

arXiv:1205.5816 ] [

INSPIRE ].

ADS CrossRef [11]

T. Plehn, M. Spannowsky and M. Takeuchi,

Stop searches in 2012 ,

JHEP
08 (2012) 091 [

arXiv:1205.2696 ] [

INSPIRE ].

ADS CrossRef [12]

J. Cao, C. Han, L. Wu, J.M. Yang and Y. Zhang,

Probing Natural SUSY from Stop Pair Production at the LHC ,

arXiv:1206.3865 [

INSPIRE ].

[13]

B. Dutta, T. Kamon, N. Kolev, K. Sinha and K. Wang,

Searching for Top Squarks at the LHC in Fully Hadronic Final State ,

Phys. Rev .

D 86 (2012) 075004 [

arXiv:1207.1873 ] [

INSPIRE ].

ADS [14]

S.P. Martin,

A Supersymmetry primer ,

hep-ph/9709356 [

INSPIRE ].

[15]

T. Appelquist, H.-C. Cheng and B.A. Dobrescu,

Bounds on universal extra dimensions ,

Phys. Rev .

D 64 (2001) 035002 [

hep-ph/0012100 ] [

INSPIRE ].

ADS [16]

B.A. Dobrescu and E. Pontón,

Chiral compactification on a square ,

JHEP
03 (2004) 071 [

hep-th/0401032 ] [

INSPIRE ].

ADS CrossRef [17]

G. Burdman, B.A. Dobrescu and E. Ponton,

Six-dimensional gauge theory on the chiral square ,

JHEP
02 (2006) 033 [

hep-ph/0506334 ] [

INSPIRE ].

MathSciNet ADS CrossRef [18]

H. Cai, H.-C. Cheng and J. Terning,

A Spin-1 Top Quark Superpartner ,

Phys. Rev. Lett .

101 (2008) 171805 [

arXiv:0806.0386 ] [

INSPIRE ].

ADS CrossRef [19]

J. Pumplin et al.,

New generation of parton distributions with uncertainties from global QCD analysis ,

JHEP
07 (2002) 012 [

hep-ph/0201195 ] [

INSPIRE ].

ADS CrossRef [20]

W. Beenakker et al.,

Supersymmetric top and bottom squark production at hadron colliders ,

JHEP
08 (2010) 098 [

arXiv:1006.4771 ] [

INSPIRE ].

ADS CrossRef [21]

M. Cacciari, M. Czakon, M. Mangano, A. Mitov and P. Nason,

Top-pair production at hadron colliders with next-to-next-to-leading logarithmic soft-gluon resummation ,

Phys. Lett .

B 710 (2012) 612 [

arXiv:1111.5869 ] [

INSPIRE ].

ADS [22]

CDF collaboration, T. Aaltonen et al.,

Search for Production of Heavy Particles Decaying to Top Quarks and Invisible Particles in
\(p\overline{p}\)
collisions at
\(\sqrt{s}=1.96\;TeV\) ,

Phys. Rev. Lett .

106 (2011) 191801 [

arXiv:1103.2482 ] [

INSPIRE ].

ADS CrossRef [23]

D0 collaboration, V.M. Abazov et al.,

Search for scalar bottom quarks and third-generation leptoquarks in pp
^{−}
bar collisions at
\(\sqrt{s}=1.96\;TeV\) ,

Phys. Lett.
B 693 (2010) 95 [

arXiv:1005.2222 ] [

INSPIRE ].

ADS [24]

M.S. Carena, J. Hubisz, M. Perelstein and P. Verdier,

Collider signature of T-quarks ,

Phys. Rev .

D 75 (2007) 091701 [

hep-ph/0610156 ] [

INSPIRE ].

ADS [25]

ATLAS collaboration, G. Aad et al.,

Search for New Phenomena in
\(t\overline{t}\)
Events With Large Missing Transverse Momentum in Proton-Proton Collisions at
\(\sqrt{s}=7\;TeV\)
with the ATLAS Detector ,

Phys. Rev. Lett .

108 (2012) 041805 [

arXiv:1109.4725 ] [

INSPIRE ].

ADS CrossRef [26]

ATLAS collaboration,

Search for a heavy top partner in final states with two leptons with the ATLAS detector ,

ATLAS-CONF-2012-071 (2012).

[27]

ATLAS collaboration,

Search for direct top squark pair production in final states with one isolated lepton, jets and missing transverse momentum in
\(\sqrt{s}=7\;TeV\)
pp collisions using 4.7 ifb of ATLAS data ,

ATLAS-CONF-2012-073 (2012).

[28]

ATLAS collaboration,

Search for a supersymmetric partner of the top quark in final states with jets and missing transverse momentum at
\(\sqrt{s}=7\;TeV\)
with the ATLAS detector ,

ATLAS-CONF-2012-074 (2012).

[29]

S. Sharma, Searches for SUSY in hadronic final states at CMS , talk at the 36th International Conference for High Energy Physics (ICHEP 2012) , Melbourne, Australia, 4–11 July 2012.

[30]

C. Rogan, Interpretations of CMS SUSY analyses in the simplified model space (SMS) , talk at the 36th International Conference for High Energy Physics (ICHEP 2012) , Melbourne, Australia, 4–11 July 2012.

[31]

R. Essig, E. Izaguirre, J. Kaplan and J.G. Wacker,

Heavy Flavor Simplified Models at the LHC ,

JHEP
01 (2012) 074 [

arXiv:1110.6443 ] [

INSPIRE ].

ADS CrossRef [32]

Y. Kats, P. Meade, M. Reece and D. Shih,

The Status of GMSB After 1/fb at the LHC ,

JHEP
02 (2012) 115 [

arXiv:1110.6444 ] [

INSPIRE ].

ADS CrossRef [33]

M. Papucci, J.T. Ruderman and A. Weiler,

Natural SUSY Endures ,

JHEP
09 (2012) 035 [

arXiv:1110.6926 ] [

INSPIRE ].

ADS CrossRef [34]

X.-J. Bi, Q.-S. Yan and P.-F. Yin,

Probing Light Stop Pairs at the LHC ,

Phys. Rev .

D 85 (2012) 035005 [

arXiv:1111.2250 ] [

INSPIRE ].

ADS [35]

C. Brust, A. Katz, S. Lawrence and R. Sundrum,

SUSY, the Third Generation and the LHC ,

JHEP
03 (2012) 103 [

arXiv:1110.6670 ] [

INSPIRE ].

ADS CrossRef [36]

N. Desai and B. Mukhopadhyaya,

Constraints on supersymmetry with light third family from LHC data ,

JHEP
05 (2012) 057 [

arXiv:1111.2830 ] [

INSPIRE ].

ADS CrossRef [37]

A. Choudhury and A. Datta,

New limits on top squark NLSP from LHC 4.7 f b
^{−1}
data ,

Mod. Phys. Lett .

A 27 (2012) 1250188 [

arXiv:1207.1846 ] [

INSPIRE ].

ADS [38]

A. Lazopoulos, T. McElmurry, K. Melnikov and F. Petriello,

Next-to-leading order QCD corrections to
\(t\overline{t}Z\)
production at the LHC ,

Phys. Lett .

B 666 (2008) 62 [

arXiv:0804.2220 ] [

INSPIRE ].

ADS [39]

A. Kardos, Z. Trócsányi and C. Papadopoulos,

Top quark pair production in association with a Z-boson at NLO accuracy ,

Phys. Rev .

D 85 (2012) 054015 [

arXiv:1111.0610 ] [

INSPIRE ].

ADS [40]

M. Garzelli, A. Kardos, C. Papadopoulos and Z. Trócsányi,

Z0 - boson production in association with a top anti-top pair at NLO accuracy with parton shower effects ,

Phys. Rev .

D 85 (2012) 074022 [

arXiv:1111.1444 ] [

INSPIRE ].

ADS [41]

M. Beneke, P. Falgari, S. Klein and C. Schwinn,

Hadronic top-quark pair production with NNLL threshold resummation ,

Nucl. Phys .

B 855 (2012) 695 [

arXiv:1109.1536 ] [

INSPIRE ].

ADS CrossRef [42]

ATLAS collaboration, G. Aad et al.,

Measurement of the top quark pair cross section with ATLAS in pp collisions at
\(\sqrt{s}=7\;TeV\)
using final states with an electron or a muon and a hadronically decaying τ lepton ,

Phys. Lett .

B 717 (2012) 89 [

arXiv:1205.2067 ] [

INSPIRE ].

ADS [43]

A. Pukhov,

CalcHEP 2.3: MSSM, structure functions, event generation, batchs and generation of matrix elements for other packages ,

hep-ph/0412191 [

INSPIRE ].

[44]

A. Pukhov, A. Belyaev and N. Christensen,

CalcHEP - a package for calculation of Feynman diagrams and integration over multi-particle phase space ,

http://theory.sinp.msu.ru/~pukhov/calchep.html .

[45]

T. Sjöstrand, S. Mrenna and P.Z. Skands,

PYTHIA 6.4 Physics and Manual ,

JHEP
05 (2006) 026 [

hep-ph/0603175 ] [

INSPIRE ].

ADS CrossRef [46]

C. Lester and D. Summers,

Measuring masses of semiinvisibly decaying particles pair produced at hadron colliders ,

Phys. Lett.
B 463 (1999) 99 [

hep-ph/9906349 ] [

INSPIRE ].

ADS [47]

A.J. Barr and C.G. Lester,

A Review of the Mass Measurement Techniques proposed for the Large Hadron Collider ,

J. Phys .

G 37 (2010) 123001 [

arXiv:1004.2732 ] [

INSPIRE ].

ADS [48]

A. Barr et al.,

Guide to transverse projections and mass-constraining variables ,

Phys. Rev .

D 84 (2011) 095031 [

arXiv:1105.2977 ] [

INSPIRE ].

ADS [49]

J. Alwall, A. Freitas and O. Mattelaer,

Measuring Sparticles with the Matrix Element ,

AIP Conf. Proc .

1200 (2010) 442 [

arXiv:0910.2522 ] [

INSPIRE ].

ADS CrossRef [50]

P. Konar, K. Kong, K.T. Matchev and M. Park,

Superpartner Mass Measurement Technique using 1

D Orthogonal Decompositions of the Cambridge Transverse Mass Variable M
_{T2} ,

Phys. Rev. Lett .

105 (2010) 051802 [

arXiv:0910.3679 ] [

INSPIRE ].

ADS CrossRef [51]

T. Cohen, E. Kuflik and K.M. Zurek,

Extracting the Dark Matter Mass from Single Stage Cascade Decays at the LHC ,

JHEP
11 (2010) 008 [

arXiv:1003.2204 ] [

INSPIRE ].

ADS CrossRef [52]

T. Han, I.-W. Kim and J. Song,

Kinematic Cusps: Determining the Missing Particle Mass at Colliders ,

Phys. Lett .

B 693 (2010) 575 [

arXiv:0906.5009 ] [

INSPIRE ].

ADS [53]

T. Han, I.-W. Kim and J. Song,

Kinematic Cusps With Two Missing Particles I: Antler Decay Topology ,

arXiv:1206.5633 [

INSPIRE ].

[54]

T. Han, I.-W. Kim and J. Song,

Kinematic Cusps with Two Missing Particles II: Cascade Decay Topology ,

arXiv:1206.5641 [

INSPIRE ].

[55]

G.L. Kane, A.A. Petrov, J. Shao and L.-T. Wang,

Initial determination of the spins of the gluino and squarks at LHC ,

J. Phys .

G 37 (2010) 045004 [

arXiv:0805.1397 ] [

INSPIRE ].

ADS [56]

A. Barr,

Measuring slepton spin at the LHC ,

JHEP
02 (2006) 042 [

hep-ph/0511115 ] [

INSPIRE ].

ADS CrossRef [57]

C.-Y. Chen and A. Freitas,

General analysis of signals with two leptons and missing energy at the Large Hadron Collider ,

JHEP
02 (2011) 002 [

arXiv:1011.5276 ] [

INSPIRE ].

ADS © SISSA, Trieste, Italy 2012

Authors and Affiliations Chien-Yi Chen Ayres Freitas Email author Tao Han Keith S. M. Lee 1. Department of Physics Carnegie Mellon University Pittsburgh U.S.A. 2. PITTsburgh Particle physics, Astrophysics, and Cosmology Center (PITT PACC), Department of Physics & Astronomy University of Pittsburgh Pittsburgh U.S.A.