den sector effects on double Hi duction near threshold Rogerio Rosenfeld Instituto de Física Teórica UNESP VIII Simpósio Latinoamericano de Física de Altas Energias SILAFAE 2010 – Valparaíso – Chile Work done with Alexandra Oliveira (arXiv:1009.4 Dedicated to the memory of Olivier Espinosa
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Hidden sector effects on double Higgs production near threshold Rogerio Rosenfeld Rogerio Rosenfeld Instituto de Física Teórica Instituto de Física Teórica.
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Hidden sector effects on double Higgs production near threshold
Rogerio Rosenfeld
Instituto de Física Teórica UNESP
VIII Simpósio Latinoamericano de Física de Altas Energias SILAFAE 2010 – Valparaíso – Chile
Work done with Alexandra Oliveira (arXiv:1009.4497)
Dedicated to the memory of Olivier Espinosa
Idea:
• many BSM models with new interactions in the Higgs sector: “Higgs portal”
• new interactions in the Higgs sector could lead to enhancements in Higgs pair production near threshold (light Higgs has weak self-interactions)
H-H bound states (Higgsium, Grinstein and Trott 07)
• gluon distribution functions are largest near threshold.
...
Idea:
Effective ggHH vertexPlehn, Spira and Zerwas (96)
new scalar particle
Possible enhancement in Higgs pair production near thresholddue to new physics:
Analogous to Sommerfeld enhancements invoked in annihilation of DM particles and similar to QCD corrections to top quark pair production near threshold:
Fadin and Khoze(87) Fadin, Khoze and Sjostrand (90)Strassler and Peskin (91)Hagiwara, Sumino and Yokoya (08)
Toy model:
Use optical theorem to find correction to the cross section:
is the amplitude for gg scattering via a higgs loop.
Goal: compute this amplitude in the nonrelativistic limit includingcontributions from the hidden sector.
Summing up ladder diagrams:
Integral Bethe-Salpeter equation:
Complete scattering amplitude
Nonrelativistic approximation (after Fourier transform) results in a Schroedinger-like equation:
Solve equation numerically.
Enhancement of the cross section:
Enhancement depends on:
“strength of new interaction”
Solid line: SMk= 0.01, 0.1, 0.3
Solid line: SMk= 0.1, 0.7 and 1
Large enhancements for large couplings:
Peaks are due to HH bound states below threshold
Conclusions
• Initial study on the enhancement of Higgs pair production near threshold due to new physics in Higgs sector;
• Enhancement occurs for strong couplings;
• Simplest model with an extra scalar field does not lead to enhancements because of mixing:
• Signal: excess of 4 gauge bosons production below Higgs pair threshold (small background)
ICTP-South American Institute for Fundamental Research
November 8
Agreement between the State University of São Paulo (UNESP) and ICTP:• new institute will be hosted by IFT-UNESP• UNESP will hire 5 researchers in 5 years (light teaching load) selected by aninternational scientific committee and 3 administrative staff• ICTP will help in organizing events and raising funds