/ < < / π - X q- γ * μ + q μ - p X
1 = 1 + G + + L q L g
dσ d 4 qdω = α em Fq ˆσ U [( + S T cos φ 1+D [sin θ]au { A sin φ S T sin φ S + + D [sin θ] ) cos φ ( A sin(φ+φ S) T sin(φ + φ S )+ +A sin(φ φ S) T sin(φ φ S ) h? 1 (p) h? 1 ( ) f? 1T (p) f 1( ) )}] y π - θ p μ + φ z x y S T x φ s q T q μ - π - p z
μ4 4 μ l + N (")! l 0 + h 0 + X 5 A sin S UT / f? 1T D 1 p, γ * h X - A cos h UU / h? 1 H? 1 +... l' x φ h ST γ * l h z
PHYSICAL Sivers 関数 HERMES sin(φ-φ sin(φ-φ S) S) UTUT sin(φ-φ sin(φ-φ S) S) UTUT PRL-0.05 103, 1500 (00) 0. 0.1 K++ π 0.1 0.05 0 0 0.1 0.1 0. 0.3 0.4 0.5 0.1 0.05 x 0.3 0.4 0.5 0.6 0.7 0.8 0.1 z 0.3 0.5 PT (GeV) 0.7 0.4 0.5 0.6 0.7 y 0 0 by as much as would have been expected for a not change FIG. 4 (color online). -0.05 Our Fit 1 to HERMES preliminary deuteron-target data. The line labels are sam sizable 1 -suppressed contribution, e.g., one from lon- - 0.1 Boer-Mulders 関数 Acos φ 0 sin(φ-φs) UT π- cos φ 0.05 blind), gives a resulting asym Boer-Mulders Boer-Mu 0.5 than for 1$þ. Cahn+BM Cahn Ph [GeV] Figure 4 shows our Fit 1 to 0.15 π π π deuteron target. πwe have negle 0: < xf < 1: () 0.1 FIG. (color online). Sivers amplitudes for!þ (left) andisospin Kþ symmetry to rela used 0.05 (right) functions of z or Ph?, to compared for#week twoofending different neutron to those of Note that as Boer-Mulders contributions $þ and $ 0 R E V Iranges E W inl E T T E R S OCTOBER 00 Q (high-q points are slightly shifted horizontally). -0.05 The corresponding fraction of pions and kaons stemming from HERMES Proton -0.1 + + Cahn Cahn Q < 4 GeV Cahn π K 0. vector exclusive mesons, extractedboer-mulders from a Monte CarloBoer-Mulders simulaboer-mulders Boer-Mu -0.15 + + Q > 4 GeV Cahn+BM Cahn 0.15 πcahn+bm πcahn+bm π+ π+ tion, is provided in bottom panels. A sin(φ-φs) UT 深非弾性散乱を用いた Sivers 関数等の測定 0 ; Q-0.15 > 1 GeV W 0.6 > 10 GeV PT > 0.4 0:05 0.6 GeV Boer-Mulders 0.5; 1Boer-Mulders 0.4 Cahn+BM Cahn+BM Ph [GeV] 0:03 < x < 1:0; 0: < zz < 1:0; 0:3 < y < 0:85 z -0.1 K0 π -0.1 Q -0.1 Acos φ cos φ Acos φ Fig. 7. Sivers asymmetry against x, z and pht for all charged pions and kaons samples from 003 004 data, and all K S0 s sample from 00 004 data. A sin(φ-φs) UT Q [GeV ] Deuteron sin(φ-φs) UT COMPASS 133 COMPASS Collaboration / Physics Letters B 673 (00) 17 135 sin(φ-φs) UT sin(φ-φs) UT sin(φ-φs) UT Proton NVM h / Nh Cahn Cahn Cahn gitudinal photons to spin-(in)dependent cross section. Boer-Mulders Boer-Mulders Boer-Mulders -0.15 Let us now come to Fit.Cahn+BM In this case, th The experimental cuts of COMPASS experiment Cahn+BM Cahn+BM þ However, while! asymmetries for two Q re0 (which runs with a deuteron target) are and!d are found to be 0 0.1 0.15 gions are fully consistent, re is a hint of systematically π π π π Q! 1 GeV ; þ W > 5 GeV ;! ¼ :1 $ 0:1;! ¼ %1:111 $ 0: u d 0.1 asymmetries in large-q region. -0.1 0 smaller K -0.1 0.5 1 0.4 0.6 0.5 1 0.05 0.4 0.6 + interesting 0: < z < 0:85; An0:1 " y " 0:facetPTof> 0:1 data GeV: is difference in 0.05 π π 0 Ph [GeV] z z verypclose and are toofthose of Fit 1 (again, h [GeV] 0.5!þ and-0.05 K þ amplitudes shown in (31)Fig. 4. On basis positivity bound). Thus, x-dependen u-quark -0.1 dominance, i.e., dominant contribution to!þ 0 þ þ FIG. our þ(color SiversCahn amplitudes! (left) and Kis essentially Mulders functions same In Fig. 5 we show fit to online). COMPASS data. One for Cahn Cahn 0 and K production from scattering off u quarks, one might Boer-Mulders Boer-Mulders Boer-Mulders -0.15 However, " per degreecahn+bm clearly sees that(right) PTasdependence inof freedom o functions of se z Cahn+BM orþdata Ph?,iscompared for twodifferent Cahn+BM þ amplitudes -0.05 =d:o:f: naively expect that! and K should be compatible withranges HERMES one and hard to understand cantly smaller: " ¼ :41. In Figs. points are slightly horizontally). in Q (high-q 0.1 0. 0.3 0.4 0.5 0.3 0.4 shifted 0.5 0.6 0.7 0.8 0.1 0.3 0.5 0.7 0.4 þ þ cos# -1 0.4 0.6 0.5 1 similar. The difference in! and K amplitudes may oretically. results of Fit for A compared to The corresponding fraction of pions and kaons stemming from 10 0. + z PT (GeV) x K thus pointvector to a significant role offrom or quark Carlo flavors, e.g., x z Ph [GeV] exclusive mesons, extracted a Monte simuladeuteron 0.1 quarks. Strictly speaking, evencompass in case of scattering tion, isonline). provided bottom panels. FIG. sea (color OurinFit 1 to HERMES preliminary proton-target data [17]. The dot-dashe PRL 103(00)1500 dotted line isoff u Boer-Mulder contribution, continuous line isd 1,resulting asymmetry taking FIG. 1. Sivers amplitudes for pions, charged kaons, and solely quarks, fragmentation function con0.15 π+ π+ π+ 0 pion-difference asymmetry (as denoted in panels) as functained in 0.1 both numerator and denominator in Eq. (), not change by as much as would have been expected for a tions of x, z, or Ph?. The systematic uncertainty is given as a does not10.05 cancel in general as it appears in convolution sizable Q -suppressed contribution, e.g., one from lonband at K-bottom of each panel. In addition re is a 7.3% integrals. 0 This can lead not only 11406-5 to additional 0.1 scale uncertainty from target-polarization measurement. -0.05 gitudinal photons to spin-(in)dependent z dependences, but also to a difference incross sizesection. of þ -0.1 However, while! asymmetries for Cahn two Q recahn Cahn 0 Boer-Mulders Boer-Mulders Boer-Mulders -0.15 gions are fully consistent, re is a hint ofcahn+bm systematically Cahn+BM Cahn+BM amplitudes for Ph? * 0:4 GeV and are consistent with þ -0.1 + + smaller K in large-q region. predicted linear decrease in limit of Ph? going to Q < Q (xi) Kπ π asymmetries 0.15 π π + An interesting facet (xi) data is difference in π π Q of > Q 0.1 zero. þ þ! and K amplitudes shown in Fig. 4. On basis of 0.1 0.05 In0.5 order to furr examine influence of exclusive u-quark dominance, i.e., dominant contribution to!þ 0 vector-meson decay and or possible Q1 -suppressed con0 and Kþ -0.05 production from scattering off u quarks, one might tributions, several studies were performed. Raising -0.1 Cahn naively0 expect that!þcahn and Kþ amplitudescahn should be Boer-Mulders þ Boer-Mulders Boer-Mulders lower limit of Q-1 to 4 GeV 0.4eliminates a large part of -0.15 þ 0.6 0.5 1 similar. The difference in! and K amplitudes may Cahn+BM Cahn+BM Cahn+BM 10 vector-meson contribution. Because of strong correla- -1 10 thus point to a10significant x z Ph [GeV] 0.3 0.4quark 0.5 0.6flavors, 0.7 0.1 e.g., 0.3 0.5 0.7 0. 10 role of or only tions between x and Q in data, this is presented x z sea quarks. Strictly speaking, even in case of scatteringpt (GeV) dependences. No influence of vectorfor z and P FIG. 1. Sivers h? amplitudes for pions, charged kaons, and solely off u quarks, fragmentation function D1, conplb 673(00)17 PRDdata81(010)11406 (color Fit 1 to COMPASS preliminary (deuteron target) [15,16]. The line labels are meson fraction on asymmetries isinvisible as FIG. shown in online). pion-difference asymmetry (as denoted panels) as 5functainedOur 1in both numerator and denominator in Eq. (), -1-1 Fig..ofFor shown in Fig. 3, each bin was tions x, z, orxpdependence h?. The systematic uncertainty is given as a does not cancel in10general asx it appears in 10 convolution x 第 5 回高エネルギーQCD 核子構造勉強会 山形大理 糠塚元気 7 / 0 regions below and above divided intobottom two Qof each band at panel. In addition re is acorre7.3%
h? 1 DY = h? 1 DIS
偏極 DY 実験計画 横偏極陽子標的 π- ビーム 運動量 強度 spill 長 サイクル 10 GeV/c 10 π/spill 015 年 5 月から約 5 ヶ月間のデータ収集 014 年 10 月 1月に試験ラン 018 年にも測定を予定.6 s 33.6 s 大角度(< 電磁石 π- 小角度(< 180 mrad)電磁石 偏極標的 第 5 回高エネルギーQCD 核子構造勉強会 RICH μ識別 30 mrad) μ識別 μ μ 電磁カロリーメータ ハドロンカロリーメータ ハドロンカロリーメータ 電磁カロリーメータ 山形大理 糠塚元気 10 / 0
< < dn +- µµ/dm (50MeV/c ) 10 4 10 3 10 J/ NA50, p+pb at 400 GeV ' DRELL-YAN OPEN CHARM EMPTY-TARGET COMB. BACKGROUND 10 1 3 4 5 6 7 M µµ (GeV/c )
< < dn +- µµ/dm (50MeV/c ) 10 4 10 3 10 J/ NA50, p+pb at 400 GeV ' DRELL-YAN OPEN CHARM EMPTY-TARGET COMB. BACKGROUND 10 1 3 4 5 6 7 M µµ (GeV/c )
< < dn +- µµ/dm (50MeV/c ) 10 4 10 3 10 J/ NA50, p+pb at 400 GeV ' DRELL-YAN OPEN CHARM EMPTY-TARGET COMB. BACKGROUND 10 1 3 4 5 6 7 M µµ (GeV/c )
xbj に対するアクセプタンス アクセプタンスの ある領域 アクセプタンスの ある領域 +<< *. +<< *. gure 6: Dimuon mass range 4 GeV/cFigure. The left upper panel shows firstgev/c kt -. T 7: Dimuon mass range.5 ment π of u-quark Sivers PDF calculated at Q = 5 GeV Ref. [134]. The moment of u-quarkfrom Sivers PDF calculated at X t lower panel shows covered kinematiclower region in xpshows versus x (in red). kinematic In rightregion + panel covered q Compass * per and lower panels acceptance is shown aspanels a function of xp andacceptanc xf, upper and lower Compass γ pectively. respectively. μ q μ +µ M <.5 GeV/c The conclusions from s µ robability that same muon was registered in both SAS.and LAS, refore ilar to those obtained for high mass range: t X can exceed 100%. sum ofp three contributions nearly corresponds to acceptance of The geometrical acceptance is calculated as ratio between maximal number of events 第 5 回高エネルギーQCD 核子構造勉強会 山形大理 糠塚元気 1 / 0
xbj に対するアクセプタンス アクセプタンスの ある領域 アクセプタンスの ある領域 +<< *. +<< *. gure 6: Dimuon mass range 4 GeV/cFigure. The left upper panel shows firstgev/c kt -. T 7: Dimuon mass range.5 ment π of u-quark Sivers PDF calculated at Q = 5 GeV Ref. [134]. The moment of u-quarkfrom Sivers PDF calculated at X t lower panel shows covered kinematiclower region in xpshows versus x (in red). kinematic In rightregion + panel covered q Compass * per and lower panels acceptance is shown aspanels a function of xp andacceptanc xf, upper and lower Compass γ pectively. respectively. μ q μ +µ M <.5 GeV/c The conclusions from s µ robability that same muon was registered in both SAS.and LAS, refore ilar to those obtained for high mass range: t X can exceed 100%. sum ofp three contributions nearly corresponds to acceptance of The geometrical acceptance is calculated as ratio between maximal number of events 第 5 回高エネルギーQCD 核子構造勉強会 山形大理 糠塚元気 1 / 0
xbj に対するアクセプタンス アクセプタンスの ある領域 アクセプタンスの ある領域 +<< *. +<< *. gure 6: Dimuon mass range 4 GeV/cFigure. The left upper panel shows firstgev/c kt -. T 7: Dimuon mass range.5 ment π of u-quark Sivers PDF calculated at Q = 5 GeV Ref. [134]. The moment of u-quarkfrom Sivers PDF calculated at X t lower panel shows covered kinematiclower region in xpshows versus x (in red). kinematic In rightregion + panel covered q Compass * per and lower panels acceptance is shown aspanels a function of xp andacceptanc xf, upper and lower Compass γ p(uud) と π-(u d) の両方が pectively. respectively. μ q μ valence quark 領域 +µ M <.5 GeV/c.and The conclusions from s µ robability that same muon was registered in both uu SAS LAS, refore の DY 過程が支配的 ilar to those obtained for high mass range: t X can exceed 100%. sum ofp three contributions nearly corresponds to acceptance of The geometrical acceptance is calculated as ratio between maximal number of events 第 5 回高エネルギーQCD 核子構造勉強会 山形大理 糠塚元気 1 / 0
xbj に対するアクセプタンス アクセプタンスの ある領域 アクセプタンスの ある領域 +<< *. +<< *. gure 6: Dimuon mass range 4 GeV/cFigure. The left upper panel shows firstgev/c kt -. T 7: Dimuon mass range.5 ment π of u-quark Sivers PDF calculated at Q = 5 GeV Ref. [134]. The moment of u-quarkfrom Sivers PDF calculated at X t lower panel shows covered kinematiclower region in xpshows versus x (in red). kinematic In rightregion + panel covered q Compass * per and lower panels acceptance is shown aspanels a function of xp andacceptanc xf, upper and lower Compass γ p(uud) と π-(u d) の両方が pectively. respectively. u valence quark 領域 qu μ M <.5 GeV/c.and The conclusions from s robability that same muon was registered in both SAS LAS, refore uu の DY 過程が支配的 μ µ+ µ ilar to those obtained for high mass range: t X can exceed 100%. sum ofp three contributions nearly corresponds to acceptance of The geometrical acceptance is calculated as ratio between maximal number of events 第 5 回高エネルギーQCD 核子構造勉強会 山形大理 糠塚元気 1 / 0
ハドロンアブソーバー 目的 標的と反応しなかったπ- とμ+μ以外の２次粒子を止める 36 阻止能 40 10 5 10-4 /cm/primary π プロトタイプ シミュレーション.5 π- 160 アルミニウム ステンレス タングステン コンクリート 単位 cm 第 5 回高エネルギーQCD 核子構造勉強会 山形大理 糠塚元気 14 / 0
偏極 DY 実験用偏極陽子標的 標的物質 NH 能動核偏極法により 最大 0% の陽子 3 偏極度 標的セル 55 cm 4 cmφ セル 上流と下流の 箇所に設置し それぞれ反対向きに 偏極させる 約 1 週間おきに偏極の向きを逆転させ 幾何学的な 非対称度を打ち消す 横偏極モードで運用 核磁気共鳴 NMR を用いた偏極度測定 標的セル 第 5 回高エネルギーQCD 核子構造勉強会 π- マイクロ波ストッパー 標的セル 山形大理 糠塚元気 17 / 0
DY 実験用偏極陽子標的のアップグレード 陽子偏極度の測定 偏極度は温度に依存する 大強度 π- ビームによる偏極度の減少が心配される セル内部にコイル設置し ビーム中心での偏極度を測定する セル表面に設置 セル内部にも追加 偏極度測定のノイズ低減 水素核を含まない素材 ポリクロロ トリフルオロ エチレン を標的セルに使用する バックグラウンドの低下 第 5 回高エネルギーQCD 核子構造勉強会 F F C C F Cl n 山形大理 糠塚元気 18 / 0