LHC LHC LHCf TOTEM Predictions of s tot

陽子・陽子散乱断面積：LHCでの予言 不定性はLHCエネルギーで既に大きい ←LHCf, TOTEM Predictions of s tot COMPETE 111. 5 mb FESR (Igi-Ishida) 106. 3 mb MC event generators PYTHIA 101. 5 mb (Pomeron+Reggeon) PHOJET 119. 1 mb (multiple P exchange, unitarity) Lanshoff (revised) 125+/ 25 mb hep-ph/0604120 多くの計算がユニタリ性の効果を考慮している

証拠１：幾何的スケーリング [Stasto, Kwiecinski, Golec-Biernat 2001] 深非弾性散乱で発見された The g*-proton total cross section s(Q 2 , x) becomes a function of only one variable x= Q 2/Qs 2(x) at small x s(Q 2 , x)=f(x) , with Qs 2(x) ~1/xl , l~0. 3 determined by the fit Qs の存在を保証する重要な結果 Qs の x依存性はCGCの結果と矛盾しない g*p total cross section

証拠２：DIS at HERA [Iancu, KI, Munier ‘ 04] - Fit for the data with small x and moderate Q 2 x < 0. 01 & 0. 045 < Q 2 <45 Ge. V 2 - Analytic solutions to Balitsky. Kovchegov equation built in: geometric scaling & its violation, saturation. - Only 3 parameters: proton radius R, x 0 (nonpert. ) and l for QS 2(x)=(x 0/x)l Ge. V 2 - Good agreement with the data x 0 = 0. 26 x 10 -4, l = 0. 25 Red line : the CGC fit Blue line : BFKL w/o saturation - Also works well for vector meson (r, f) production, diffractive F 2, FL [Forshaw et al, Goncalves, Machado ’ 04]

証拠３：deuteron-Au at RHIC 重陽子・金衝突で前方散乱への移行　　　→　藤井氏の講演 Rd. Au [Kharzeev, Kovchegov, and Tuchin] h(h-+h+)/2 前方では陽子・陽子散乱に比べて抑制がある 　←　CGCにおける原子核の飽和現象　実験データの振る舞いと定性的に一致 解析的に調べると [Iancu, KI, Triantafyllopoulos] Cronin enhancement – due to multiple collision a la Glauber, which can be described by classical saturation model (Mc. Lerran-Venugopalan model) Suppression -- due to quantum evolution (coherent scattering) Rp. A ~ j. A(x, k) /A jp (x, k) : proton (far from saturation) evolves faster than nucleus (close to saturation)

ダイアグラム的表現 3 IP vertex =gluon recombination IP BFKL ladder hard Pomeron fan diagram 横平面図 Higher energies BFKL+soft physics CGC ヴァレンス的　　　　グルオン増殖　　　　グルオン飽和　　　　　　Black disk expansion 　希薄ガス　　　　　　　BFKL　　　　　　カラーグラス凝縮　　　　s ~ ln 2(1/x) Froissart

Simulation by H. J. Drescher http: //th. physik. uni-frankfurt. de/~drescher/ Electron/positron Proton/neutron Photon muon