Abstract
The ATLAS and CMS experiments at the LHC have reported an excess of diphoton events with invariant mass around 750 GeV, with local significance of about 3.6 σ and 2.6 σ, respectively. We entertain the possibility that this excess is due to new physics, in which case the data suggest a new particle with 13 TeV LHC production cross section times diphoton branching ratio of about 5 fb. Interestingly, ATLAS reports a mild preference for a sizeable width for the signal of about 45 GeV; this result appears consistent with CMS, and is further supported by improving the compatibility of the 8 TeV and 13 TeV analyses. We focus on the possibility that the new state is a scalar. First, we show that, in addition to the new state that is needed directly to produce the diphoton bump, yet more new particles beyond the Standard Model are needed to induce diphoton decay rate of the right size. Second, we note that if the excess is attributed to the Breit-Wigner peak of a single new state, then the signal strength and width — taken together — suggest a total LHC production cross section of order 105 fb. Restricting to perturbative models without ad-hoc introduction of many new states or exotic charges, we reach the following conclusions: (i) Gluon-fusion cannot explain the required large production cross section. (ii) Tree level production from initial state quarks cannot explain the required branching ratio to two photons. (iii) Tree level production is constrained by flavor data as well as LHC Run-I and Tevatron dijet analyses. Insisting on a large width we are led to suggest that more than one scalar states, nearly degenerate in mass, could conspire to produce an observed wide bump.
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References
ATLAS collaboration, Search for resonances decaying to photon pairs in 3.2 fb −1 of pp collisions at \( \sqrt{s}=13 \) TeV with the ATLAS detector, ATLAS-CONF-2015-081 (2015).
CMS collaboration, Search for new physics in high mass diphoton events in proton-proton collisions at \( \sqrt{s}=13 \) TeV, CMS-PAS-EXO-15-004 (2015).
LHC Higgs Cross Section Working Group collaboration, J.R. Andersen et al., Handbook of LHC Higgs Cross Sections: 3. Higgs Properties, arXiv:1307.1347 [INSPIRE].
ATLAS collaboration, A search for \( t\overline{t} \) resonances using lepton-plus-jets events in proton-proton collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, JHEP 08 (2015) 148 [arXiv:1505.07018] [INSPIRE].
CMS collaboration, Search for resonant \( t\overline{t} \) production in proton-proton collisions at \( \sqrt{s}=8 \) TeV, Phys. Rev. D 93 (2016) 012001 [arXiv:1506.03062] [INSPIRE].
R. Mertig, M. Böhm and A. Denner, FEYN CALC: Computer algebraic calculation of Feynman amplitudes, Comput. Phys. Commun. 64 (1991) 345 [INSPIRE].
V. Shtabovenko, R. Mertig and F. Orellana, New Developments in FeynCalc 9.0, arXiv:1601.01167 [INSPIRE].
A.D. Martin, W.J. Stirling, R.S. Thorne and G. Watt, Parton distributions for the LHC, Eur. Phys. J. C 63 (2009) 189 [arXiv:0901.0002] [INSPIRE].
M. Czakon, P. Fiedler and A. Mitov, Total Top-Quark Pair-Production Cross Section at Hadron Colliders Through O(α 4 S ), Phys. Rev. Lett. 110 (2013) 252004 [arXiv:1303.6254] [INSPIRE].
ATLAS collaboration, Search for a high-mass Higgs boson decaying to a W boson pair in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, JHEP 01 (2016) 032 [arXiv:1509.00389] [INSPIRE].
B.A. Kniehl and M. Spira, Low-energy theorems in Higgs physics, Z. Phys. C 69 (1995) 77 [hep-ph/9505225] [INSPIRE].
J. Alwall et al., The automated computation of tree-level and next-to-leading order differential cross sections and their matching to parton shower simulations, JHEP 07 (2014) 079 [arXiv:1405.0301] [INSPIRE].
K. Blum, Y. Hochberg and Y. Nir, Scalar-mediated \( t\overline{t} \) forward-backward asymmetry, JHEP 10 (2011) 124 [arXiv:1107.4350] [INSPIRE].
ATLAS collaboration, Search for new phenomena in the dijet mass distribution using p − p collision data at \( \sqrt{s}=8 \) TeV with the ATLAS detector, Phys. Rev. D 91 (2015) 052007 [arXiv:1407.1376] [INSPIRE].
CMS Collaboration, Search for Resonances Decaying to Dijet Final States at \( \sqrt{s}=8 \) TeV with Scouting Data, CMS-PAS-EXO-14-005 (2014).
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] [INSPIRE].
D. Buttazzo, A. Greljo and D. Marzocca, Knocking on new physics’ door with a scalar resonance, Eur. Phys. J. C 76 (2016) 116 [arXiv:1512.04929] [INSPIRE].
M. Low, A. Tesi and L.-T. Wang, A pseudoscalar decaying to photon pairs in the early LHC Run 2 data, JHEP 03 (2016) 108 [arXiv:1512.05328] [INSPIRE].
R. Franceschini, G.F. Giudice, J.F. Kamenik, M. McCullough, A. Pomarol, R. Rattazzi et al., What is the γγ resonance at 750 GeV?, JHEP 03 (2016) 144 [arXiv:1512.04933] [INSPIRE].
J. Ellis, S.A.R. Ellis, J. Quevillon, V. Sanz and T. You, On the Interpretation of a Possible ∼ 750 GeV Particle Decaying into γγ, JHEP 03 (2016) 176 [arXiv:1512.05327] [INSPIRE].
A. Falkowski, O. Slone and T. Volansky, Phenomenology of a 750 GeV Singlet, JHEP 02 (2016)152 [arXiv:1512.05777] [INSPIRE].
A. Djouadi, M. Spira and P.M. Zerwas, Two photon decay widths of Higgs particles, Phys. Lett. B 311 (1993) 255 [hep-ph/9305335] [INSPIRE].
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Aloni, D., Blum, K., Dery, A. et al. On a possible large width 750 GeV diphoton resonance at ATLAS and CMS. J. High Energ. Phys. 2016, 17 (2016). https://doi.org/10.1007/JHEP08(2016)017
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DOI: https://doi.org/10.1007/JHEP08(2016)017