Quantum Critical Higgs: from AdS 5 to colliders
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Springer
Received: October 5, 2019 Accepted: January 10, 2020 Published: February 4, 2020
Ali Shayegan Shirazi and John Terning Department of Physics, University of California, One Shields Ave., Davis, California 95616, U.S.A.
E-mail: [email protected], [email protected] Abstract: We examine distinctive signatures of Quantum Critical Higgs models at the LHC and future higher energy colliders. In these models the Higgs boson is part of a conformal sector that is softly broken at a threshold scale, and generically the scaling dimension of the Higgs is larger than in the Standard Model. In particular we examine the gg → H → ZZ, gg → H → γγ, and gg → Z → HZ channels to see how the cross sections deviate from the Standard Model in the high invariant mass region. In order to perform the calculations we use 5D duals of Quantum Critical Higgs models using the AdS/CFT correspondence, with a soft wall to break the conformal symmetry. Keywords: Phenomenological Models, Phenomenology of Field Theories in Higher Dimensions ArXiv ePrint: 1908.06186
c The Authors. Open Access, Article funded by SCOAP3 .
https://doi.org/10.1007/JHEP02(2020)026
JHEP02(2020)026
Quantum Critical Higgs: from AdS5 to colliders
Contents 1 Introduction
1
2 The 1PI effective action
2
3 QCH from AdS5
5 11
5 QCH in collider physics 5.1 gg → ZZ → ```` 5.2 gg → γγ 5.3 gg → HZ
14 15 18 20
6 Conclusions
21
A The spectrum of scalar fields in AdS/Broken-CFT
22
B Backreaction of the scalar field in the minimal AdS/QCH model
22
C QCH in MadGraph
23
1
Introduction
The major unsolved problem of the Standard Model (SM) is the hierarchy problem. This problem could have been resolved by technicolor, supersymmetry, or compositeness, but technicolor has been ruled out, and there is an abundant lack of evidence for the latter two possibilities at low energies. Thus we may need to explore new paradigms in order to find a solution, and it may be helpful to approach this problem using a different perspective — using the language of condensed matter physics. A condensed matter system that exhibits a phase transition at zero temperature as another parameter of the system (like pressure or doping concentration) is changed, undergoes a quantum phase transition since there are only quantum fluctuations rather than the usual thermal fluctuations [1]. Typically in such phase transitions we need to tune the parameters of the system to be close to the critical point. The Higgs sector of SM is in fact very similar to a Landau-Ginsburg model. The hierarchy problem is tantamount to the fact that in order for the Higgs VEV to be small we need to be extremely close to the critical point, and hence must fine-tune the parameters of the model. If the theory is a good description of nature up to the Planck scale, a one part in 1034 change of the Higgs mass term will push the theory far from its critical point. At the critical point, the Higgs mass vanishes, the correlation length
–1–
JHEP02(2020)026
4 Minimal coupling of AdS-QCH
2
The 1PI effective
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