Energy calibration at high-energy photon colliders

Abstract

Calibration of the absolute energy scale at high-energy photon (gamma-gamma, gamma-electron) colliders is discussed. The luminosity spectrum at photon colliders is broad and has a rather sharp high-energy edge, which can be used, for example, to measure the mass of the Higgs boson in the process gamma-gamma to H or masses of charged scalars by observing the cross-section threshold. In addition to the precise knowledge of the edge energy of the luminosity spectrum, it is even more important to have a way to calibrate the absolute energy scale of the detector. At first sight, Compton scattering itself provides a unique way to determine the beam energies and produce particles of known energies that could be used for detector calibration. The energy scale is given by the electron mass m_e and laser photon energy ω_0. However, this does not work at realistic photon colliders due to large nonlinear effects in Compton scattering at the conversion region (ξ^2 \sim 0.3). It is argued that the process gamma-electron to eZ_0 provides the best way to calibrate the energy scale of the detector, where the energy scale is given by m_Z.

arXiv comment8 pages, 3 figures, Latex. Talk at Int. conf. on instrumentation for colliding beam physics (INSTR 2014), Feb. 24 - March 1, 2014, BINP, Novosibirsk. To be published in JINST

References in corpus (7)

• Measurement of the Higgs boson mass from the $H\to \gamma \gamma$ and $H\to Z{Z}^{\ast }\to 4\ell$ channels with the ATLAS detector using 25 fb${}^{-1}$ of $pp$ collision data
• TESLA Technical Design Report, Part VI, Chapter 1: The Photon Collider at TESLA
• New precision measurement of the $J/\psi$- and ${\psi }^{\prime }$ -meson masses
• Polarimeters and Energy Spectrometers for the ILC Beam Delivery System
• Physics goals and parameters of photon colliders
• Measurement of gamma-gamma and gamma-electron luminosities at photon colliders
• Precision Mass Determination of the Higgs Boson at Photon-Photon Colliders