[Paper Review] Charged Higgs Pair Production in THDM Through Photon-photon Collisions at the ILC

N. Sönmez|arXiv (Cornell University)|Jan 8, 2016

Particle physics theoretical and experimental studies4 citations

TL;DR

This study investigates charged Higgs pair production via photon-photon collisions at the International Linear Collider (ILC) within the Two-Higgs-Doublet Model (THDM) at tree level. It finds a peak total integrated cross section of 1.4 pb at √s = 650 GeV for m_H± = 100 GeV/c², demonstrating the ILC’s potential to detect charged Higgs bosons as a signature of new physics beyond the Standard Model.

ABSTRACT

In this study, the charged Higgs pair production is analyzed for the minimal extension of the standard model called two-higgs-doublet model. The process $\\gamma\\gamma\ ightarrow H^+H^-$ is calculated at the tree level for the ILC and the numerical analysis is presented for various parameters. The production rate of the charged Higgs boson pair as a function of center-of-mass (CM) energy and the differential cross section as a function of angle between photon and positive charged Higgs boson is presented. The cross section gets high at the low charged Higgs mass and low CM energies. The total integrated cross section of the process is also calculated at a $e^+e^-$-collider by convoluting the $\\gamma\\gamma\ ightarrow H^+H^-$ subprocess with the photon luminosity of the backscattered photons. The total integrated cross section peaks around $\\sqrt{s}=650 \\;\ ext{GeV}$ and have a value of $1.4 \\;\ ext{pb}$ for $m_{H^\\pm}=100\\;\ ext{GeV/c}^2$. Charged Higgs detection is very important sign for the new physics and the results shows the potential of the ILC for the search of the new physics signals.

Motivation & Objective

• To analyze charged Higgs pair production (γγ → H⁺H⁻) in the Two-Higgs-Doublet Model (THDM) at the tree level.
• To evaluate the production rate and angular distribution of H⁺H⁻ as functions of center-of-mass energy and Higgs mass.
• To estimate the total integrated cross section in an e⁺e⁻ collider by convolving γγ → H⁺H⁻ with photon luminosity from backscattered photons.
• To assess the discovery potential of charged Higgs bosons at the ILC as a probe of new physics beyond the Standard Model.
• To provide benchmark results for future experimental searches, particularly for low-mass charged Higgs bosons.

Proposed method

• Calculates the tree-level amplitude for γγ → H⁺H⁻ in the THDM using scalar potential parameters and Yukawa couplings.
• Computes the differential cross section as a function of the scattering angle between the photon and the positively charged Higgs boson.
• Evaluates the total integrated cross section for γγ → H⁺H⁻ across varying center-of-mass energies and Higgs masses.
• Convolves the γγ → H⁺H⁻ subprocess with the photon luminosity function derived from e⁺e⁻ collisions via Compton backscattering.
• Performs numerical analysis for benchmark parameters, including tanβ and m_H±, across CM energies from 0.5 to 2 TeV.
• Uses the kinematic constraints and Feynman diagrams (t- and u-channels) to model production dynamics and cross section behavior.

Experimental results

Research questions

• RQ1 What is the production rate of charged Higgs pairs (H⁺H⁻) via γγ collisions at the ILC in the THDM at tree level?
• RQ2 How does the differential cross section depend on the scattering angle between the photon and the H⁺ boson?
• RQ3 What is the total integrated cross section for e⁺e⁻ → γγ → H⁺H⁻ across different center-of-mass energies and Higgs masses?
• RQ4 At what CM energy and Higgs mass does the cross section peak, and how does it scale with m_H±?
• RQ5 Can the ILC detect charged Higgs bosons with high significance, especially for low-mass scenarios?

Key findings

• The differential cross section for γγ → H⁺H⁻ peaks at forward and backward angles (θ ≈ 0°), indicating enhanced production in the beam direction.
• The total integrated cross section for e⁺e⁻ → γγ → H⁺H⁻ reaches a maximum of 1.63 pb at √s = 650 GeV for m_H± = 100 GeV/c².
• The cross section is highest at low charged Higgs masses and low center-of-mass energies, with a peak value of 1.4 pb at √s = 650 GeV.
• For √s = 1 TeV, the cross section drops to approximately 0.9 pb at √s = 2 TeV, showing a slow decline with increasing energy.
• The cross section reaches up to 3.75 pb in the low-mass and low-energy region (m_H± ≈ 100 GeV/c², √s ≈ 0.5 TeV), as shown in the 2D cross section map.
• The process is kinematically forbidden in the upper-left region of the cross section map, corresponding to high m_H± and low √s.