Abstract
We ask what new states may lie at or below the TeV scale, with sizable flavour-dependent couplings to light quarks, putting them within reach of hadron colliders via resonant production, or in association with Standard Model states. In particular, we focus on the compatibility of such states with stringent flavour-changing neutral current and electric-dipole moment constraints. We argue that the broadest and most theoretically plausible flavour structure of the new couplings is that they are hierarchical, as are Standard Model Yukawa couplings, although the hierarchical pattern may well be different. We point out that, without the need for any more elaborate or restrictive structure, new scalars with “diquark” couplings to standard quarks are particularly immune to existing constraints, and that such scalars may arise within a variety of theoretical paradigms. In particular, there can be substantial couplings to a pair of light quarks or to one light and one heavy quark. For example, the latter possibility may provide a flavour-safe interpretation of the asymmetry in top quark production observed at the Tevatron. We thereby motivate searches for diquark scalars at the Tevatron and LHC, and argue that their discovery represents one of our best chances for new insight into the Flavour Puzzle of the Standard Model.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
M.J. Strassler and K.M. Zurek, Echoes of a hidden valley at hadron colliders, Phys. Lett. B 651 (2007) 374 [hep-ph/0604261] [SPIRES].
C. Kilic, T. Okui and R. Sundrum, Colored resonances at the Tevatron: phenomenology and discovery potential in multijets, JHEP 07 (2008) 038 [arXiv:0802.2568] [SPIRES].
C. Kilic, T. Okui and R. Sundrum, Vectorlike confinement at the LHC, JHEP 02 (2010) 018 [arXiv:0906.0577] [SPIRES].
A.V. Manohar and M.B. Wise, Flavor changing neutral currents, an extended scalar sector and the Higgs production rate at the LHC, Phys. Rev. D 74 (2006) 035009 [hep-ph/0606172] [SPIRES].
S.L. Glashow and S. Weinberg, Natural conservation laws for neutral currents, Phys. Rev. D 15 (1977) 1958 [SPIRES].
G. D’Ambrosio, G.F. Giudice, G. Isidori and A. Strumia, Minimal flavour violation: an effective field theory approach, Nucl. Phys. B 645 (2002) 155 [hep-ph/0207036] [SPIRES].
B. Gripaios, Composite leptoquarks at the LHC, JHEP 02 (2010) 045 [arXiv:0910.1789] [SPIRES].
S. Davidson and S. Descotes-Genon, Minimal flavour violation for leptoquarks, JHEP 11 (2010) 073 [arXiv:1009.1998] [SPIRES].
B. Gripaios, A. Papaefstathiou, K. Sakurai and B. Webber, Searching for third-generation composite leptoquarks at the LHC, JHEP 01 (2011) 156 [arXiv:1010.3962] [SPIRES].
S. Davidson and P. Verdier, Leptoquarks decaying to a top quark and a charged lepton at hadron colliders, Phys. Rev. D 83 (2011) 115016 [arXiv:1102.4562] [SPIRES].
Y. Nomura, M. Papucci and D. Stolarski, Flavorful supersymmetry, Phys. Rev. D 77 (2008) 075006 [arXiv:0712.2074] [SPIRES].
C.W. Bauer, Z. Ligeti, M. Schmaltz, J. Thaler and D.G.E. Walker, Supermodels for early LHC, Phys. Lett. B 690 (2010) 280 [arXiv:0909.5213] [SPIRES].
E. Ma, M. Raidal and U. Sarkar, Probing the exotic particle content beyond the standard model, Eur. Phys. J. C 8 (1999) 301 [hep-ph/9808484] [SPIRES].
J. Shu, T.M.P. Tait and K. Wang, Explorations of the top quark forward-backward asymmetry at the Tevatron, Phys. Rev. D 81 (2010) 034012 [arXiv:0911.3237] [SPIRES].
I. Dorsner, S. Fajfer, J.F. Kamenik and N. Kosnik, Light colored scalars from grand unification and the forward-backward asymmetry in top quark pair production, Phys. Rev. D 81 (2010) 055009 [arXiv:0912.0972] [SPIRES].
I. Dorsner, S. Fajfer, J.F. Kamenik and N. Kosnik, Light colored scalar as messenger of up-quark flavor dynamics in grand unified theories, Phys. Rev. D 82 (2010) 094015 [arXiv:1007.2604] [SPIRES].
M.I. Gresham, I.-W. Kim and K.M. Zurek, Searching for top flavor violating resonances, arXiv:1102.0018 [SPIRES].
K.M. Patel and P. Sharma, Forward-backward asymmetry in top quark production from light colored scalars in SO(10) model, JHEP 04 (2011) 085 [arXiv:1102.4736] [SPIRES].
B. Grinstein, A.L. Kagan, M. Trott and J. Zupan, Forward-backward asymmetry in \( t\bar{t} \) production from flavour symmetries, Phys. Rev. Lett. 107 (2011) 012002 [arXiv:1102.3374] [SPIRES].
Z. Ligeti, G.M. Tavares and M. Schmaltz, Explaining the t tbar forward-backward asymmetry without dijet or flavor anomalies, JHEP 06 (2011) 109 [arXiv:1103.2757] [SPIRES].
J.M. Arnold, M. Pospelov, M. Trott and M.B. Wise, Scalar representations and minimal flavor violation, JHEP 01 (2010) 073 [arXiv:0911.2225] [SPIRES].
K. Cheung and G.-C. Cho, Hadronic production of light color triplet Higgs bosons: an alternative signature for GUT, Phys. Rev. D 67 (2003) 075003 [hep-ph/0212063] [SPIRES].
C.D. Froggatt and H.B. Nielsen, Hierarchy of quark masses, Cabibbo angles and CP-violation, Nucl. Phys. B 147 (1979) 277 [SPIRES].
N. Arkani-Hamed and M. Schmaltz, Hierarchies without symmetries from extra dimensions, Phys. Rev. D 61 (2000) 033005 [hep-ph/9903417] [SPIRES].
D.B. Kaplan, Flavor at SSC energies: a new mechanism for dynamically generated fermion masses, Nucl. Phys. B 365 (1991) 259 [SPIRES].
Y. Grossman and M. Neubert, Neutrino masses and mixings in non-factorizable geometry, Phys. Lett. B 474 (2000) 361 [hep-ph/9912408] [SPIRES].
T. Gherghetta and A. Pomarol, Bulk fields and supersymmetry in a slice of AdS, Nucl. Phys. B 586 (2000) 141 [hep-ph/0003129] [SPIRES].
A.E. Nelson and M.J. Strassler, Suppressing flavor anarchy, JHEP 09 (2000) 030 [hep-ph/0006251] [SPIRES].
S.J. Huber and Q. Shafi, Fermion masses, mixings and proton decay in a Randall-Sundrum model, Phys. Lett. B 498 (2001) 256 [hep-ph/0010195] [SPIRES].
S.J. Huber, Flavor violation and warped geometry, Nucl. Phys. B 666 (2003) 269 [hep-ph/0303183] [SPIRES].
M. Leurer, Y. Nir and N. Seiberg, Mass matrix models, Nucl. Phys. B 398 (1993) 319 [hep-ph/9212278] [SPIRES].
M. Leurer, Y. Nir and N. Seiberg, Mass matrix models: the sequel, Nucl. Phys. B 420 (1994) 468 [hep-ph/9310320] [SPIRES].
D.E. Kaplan and T.M.P. Tait, New tools for fermion masses from extra dimensions, JHEP 11 (2001) 051 [hep-ph/0110126] [SPIRES].
S. Davidson, G. Isidori and S. Uhlig, Solving the flavour problem with hierarchical fermion wave functions, Phys. Lett. B 663 (2008) 73 [arXiv:0711.3376] [SPIRES].
S. Bar-Shalom and A. Rajaraman, Models and phenomenology of maximal flavor violation, Phys. Rev. D 77 (2008) 095011 [arXiv:0711.3193] [SPIRES].
E. Dudas, G. von Gersdorff, J. Parmentier and S. Pokorski, Flavour in supersymmetry: horizontal symmetries or wave function renormalisation, JHEP 12 (2010) 015 [arXiv:1007.5208] [SPIRES].
I. Gogoladze, Y. Mimura, N. Okada and Q. Shafi, Color triplet diquarks at the LHC, Phys. Lett. B 686 (2010) 233 [arXiv:1001.5260] [SPIRES].
K. Agashe, M. Papucci, G. Perez and D. Pirjol, Next to minimal flavor violation, hep-ph/0509117 [SPIRES].
R.N. Mohapatra, N. Okada and H.-B. Yu, Diquark Higgs at LHC, Phys. Rev. D 77 (2008) 011701 [arXiv:0709.1486] [SPIRES].
G. Isidori, Y. Nir and G. Perez, Flavor physics constraints for physics beyond the standard model, arXiv:1002.0900 [SPIRES].
M. Beneke, G. Buchalla, M. Neubert and C.T. Sachrajda, QCD factorization for B → ππ decays: Strong phases and CP-violation in the heavy quark limit, Phys. Rev. Lett. 83 (1999) 1914 [hep-ph/9905312] [SPIRES].
M. Beneke, G. Buchalla, M. Neubert and C.T. Sachrajda, QCD factorization for exclusive, non-leptonic B meson decays: General arguments and the case of heavy-light final states, Nucl. Phys. B 591 (2000) 313 [hep-ph/0006124] [SPIRES].
S. Bar-Shalom, G. Eilam and Y.-D. Yang, B → Φπ and B 0 → ΦΦ in the standard model and new bounds on R parity violation, Phys. Rev. D 67 (2003) 014007 [hep-ph/0201244] [SPIRES].
Particle Data Group collaboration, K. Nakamura et al., Review of particle physics, J. Phys. G 37 (2010) 075021 [SPIRES].
S. Weinberg, Larger Higgs exchange terms in the neutron electric dipole moment, Phys. Rev. Lett. 63 (1989) 2333 [SPIRES].
O. Lebedev, W. Loinaz and T. Takeuchi, Constraints on R-parity violating couplings from LEP/SLD hadronic observables, Phys. Rev. D 62 (2000) 015003 [hep-ph/9911479] [SPIRES].
ALEPH collaboration, et al., Precision electroweak measurements and constraints on the standard model, arXiv:1012.2367 [SPIRES].
T. Han, I. Lewis and T. McElmurry, QCD corrections to scalar diquark production at hadron colliders, JHEP 01 (2010) 123 [arXiv:0909.2666] [SPIRES].
J. Alwall et al., MadGraph/MadEvent v4: the new web generation, JHEP 09 (2007) 028 [arXiv:0706.2334] [SPIRES].
J. Pumplin et al., New generation of parton distributions with uncertainties from global QCD analysis, JHEP 07 (2002) 012 [hep-ph/0201195] [SPIRES].
CDF collaboration, F. Abe et al., Measurement of dijet angular distributions at CDF, Phys. Rev. Lett. 77 (1996) 5336 [hep-ex/9609011] [SPIRES].
D0 collaboration, V.M. Abazov et al., Measurement of dijet angular distributions at \( \sqrt {s} = 1.96 \) TeV and searches for quark compositeness and extra spatial dimensions, Phys. Rev. Lett. 103 (2009) 191803 [arXiv:0906.4819] [SPIRES].
ATLAS collaboration, G. Aad et al., Search for quark contact interactions in dijet angular distributions in pp collisions at \( \sqrt {s} = 7 \) TeV measured with the ATLAS detector, Phys. Lett. B 694 (2011) 327 [arXiv:1009.5069] [SPIRES].
CMS collaboration, V. Khachatryan et al., Measurement of dijet angular distributions and search for quark compositeness in pp collisions at 7 TeV, Phys. Rev. Lett. 106 (2011) 201804 [arXiv:1102.2020] [SPIRES].
CMS collaboration, V. Khachatryan et al., Search for dijet resonances in 7 TeV pp collisions at CMS, Phys. Rev. Lett. 105 (2010) 211801 [arXiv:1010.0203] [SPIRES].
CDF collaboration, T. Aaltonen et al., Search for new particles decaying into dijets in proton-antiproton collisions at \( \sqrt {s} = 1.96 \) TeV, Phys. Rev. D 79 (2009) 112002 [arXiv:0812.4036] [SPIRES].
CDF collaboration, T. Aaltonen et al., Evidence for a mass dependent forward-backward asymmetry in top quark pair production, Phys. Rev. D 83 (2011) 112003 [arXiv:1101.0034] [SPIRES].
Tevatron Electroweak Working Group, for the CDF and D0 collaboration, Combination of CDF and D 0 measurements of the single top production cross section, arXiv:0908.2171 [SPIRES].
Author information
Authors and Affiliations
Corresponding author
Additional information
ArXiv ePrint: 1105.3161
Rights and permissions
Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License (https://creativecommons.org/licenses/by-nc/2.0), which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
About this article
Cite this article
Giudice, G.F., Gripaios, B. & Sundrum, R. Flavourful production at hadron colliders. J. High Energ. Phys. 2011, 55 (2011). https://doi.org/10.1007/JHEP08(2011)055
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP08(2011)055