Precision Mass Determination of the Higgs Boson at Photon-Photon Colliders

We demonstrate a measurement of the Higgs boson mass by the method of energy scanning at photon-photon colliders, using the high energy edge of the photon spectrum. With an integrated luminosity of 50 $\rm{fb^{-1}}$ it is possible to measure the standard model Higgs mass to within 110 MeV in photon-photon collisions for m_h=100 GeV. As for the total width of the Higgs boson, the statistical error $\Delta\Gamma_h/\Gamma_{h \rm{SM}}=0.06$ is expected for m_h=100 GeV, if both $\Gamma(h\to\gamma\gamma)$ and $\Gamma(h\to b\bar{b})$ are fixed at the predicted standard model value.Comment: 7 pages, 4 figures, Given at 3nd International Workshop on Electron-Electron Interactions at TeV Energies, Dec 10-12, Santa Cruz, California, 199

Analysis and simulation for laser-Compton cooling of electron beams

The method of the Laser-Compton cooling of the electron beams is studied. Using a Monte Carlo code, we have evaluated the effects of the Laser-electron interaction for cooling. The optics with and without chromatic correction for cooling are examined. Problems of the optics for cooling are discussed

Estimates of Hadronic Backgrounds in Future e+e- Linear Colliders

We have estimated hadronic backgrounds for an e+e- linear collider at a center- of-mass energy of 5 TeV. In order to achieve a required luminosity in TeV e+ e- colliders, the high beamstrahlung parameter {Upsilon}, such as several thousands, is caused. In the high {Upsilon} regime, the {gamma}{gamma} luminosities due to the collision of beamstrahlung photons are calculated by using the CAIN code. According to the {gamma}{gamma} luminosity distribution, we have estimated the hadronic backgrounds of {gamma}{gamma} {yields} minijets based on the parton distributions of the Drees and Grassie model by the PYTHIA 5.7 code. The Japan Linear Collider (J LC-1) detector simulator is applied for selection performances in the detector

Estimates of Hadronic Backgrounds in Future e+e- LinearColliders

We have estimated hadronic backgrounds for an e+e- linear collider at a center- of-mass energy of 5 TeV. In order to achieve a required luminosity in TeV e+ e- colliders, the high beamstrahlung parameter {Upsilon}, such as several thousands, is caused. In the high {Upsilon} regime, the {gamma}{gamma} luminosities due to the collision of beamstrahlung photons are calculated by using the CAIN code. According to the {gamma}{gamma} luminosity distribution, we have estimated the hadronic backgrounds of {gamma}{gamma} {yields} minijets based on the parton distributions of the Drees and Grassie model by the PYTHIA 5.7 code. The Japan Linear Collider (J LC-1) detector simulator is applied for selection performances in the detector

Estimates of Hadronic Backgrounds in a 5 TeV e+e- Linear Collider

We have estimated hadronic backgrounds by {gamma}{gamma} collisions in an e{sup +}e{sup -} linear collider at a center-of-mass energy of 5 TeV. We introduce a simple ansatz, that is, a total {gamma}{gamma} cross section of {sigma}{sub {gamma}{gamma}} = ({sigma}{gamma}{sub p}){sup 2}/{sigma}{sub pp} shall be saturated by minijet productions, whose rate is controlled by p{sub t,min}({radical}s). We present that the background yields are small and the energy deposits are tinier than the collision energy of the initial electron and positron beams by a simulation

Parametric x radiation from thick crystals

The parametric x radiation from thick Si single crystals with 0.5–5 mm thickness was investigated at an electron energy of 900 MeV. As the crystal thickness increased, both intensity and angular spread reached a plateau after their increase in the thin crystal region, resulting in more brilliant x rays than Feranchuk and Ivashin's prediction [J. Phys. (Paris) 46, 1981 (1985)] for thick crystals. This behavior is consistent with the incoherent model proposed in our previous paper [Phys. Rev. Lett. 70, 3247 (1993)]