在ψ′Jψπ+π-道中的相移測量（basedonBESIII）

1、在 J/ +-道中的道中的相移測量相移測量( (based on BESIII)張振霞 (代表:張振霞, J.J.SANZ-CILLERO, 沈肖雁, 吳寧, 肖零億,鄭漢青)第十屆全國粒子物理學術(shù)會議2008/04/27Zhang Zhenxia2vWith the development of experiments, both experimental and theoretical studies on low energy and K system produced in production processes have received interests.vBut there

2、are few experimental data about the phase shift of and K system in the region 0.40.6 GeV. It will be a good idea for our BESIII to measure it due to the proper energy. vWe re-investigate the final state interactions in the J/ +- process. Here s-wave dominates and the next contribution comes from the

3、 tiny d-wave. This is crucial for exploring the s-wave phase motion through interference effect in this process.vThe information on ,k phase shift will provide a crucial ingredient in understanding the dynamics of goldstone boson and the spontaneous breaking of chiral symmetray.motivation New Ke4Cle

4、o munichZhang Zhenxia3J/+-2. 而在 J/ +-道中, J/譜的能量非常底,不存在共振態(tài).由末態(tài)定理,此過程的相移就是+-的相移. J/ +-是測量+-相移最好的衰變道Hadronization1 。在J/ +-中, 的譜上有共振態(tài),這會在理論上影響+-譜上的S波相移的提取.這是測量+-相移不可解決的困難. 其它道也存在類似情況。Zhang Zhenxia4在這個過程中,存在S波和D波,其中S波是主要的,D波占很小的成分. 理論模型Novikov-Shifman Model預(yù)言D波占420%左右.(hep-ex/9909038v1)BESIID/SM(+-)Zhang

5、 Zhenxia5衰變振幅是由 、 J/的極化矢量和末態(tài)粒子的動量構(gòu)成的所有的協(xié)變lorentz 結(jié)構(gòu)組成,然后再根據(jù)極角 *做分波展開 .振幅的構(gòu)造和相移的提取Zhang Zhenxia6From S.U.Chung,Phys.Rev.D48(1993)1225, we get:Zhang Zhenxia7Zhang Zhenxia8D 和 S波之間的相移差是: |0-2|.最后通過擬合形狀因子I1I7和 相移來獲取它們的值.For S waveFor D wave0 0 , ,2 2 : phase shift : phase shift總振幅：Zhang Zhenxia9由手征對稱性和重

6、夸克對稱性構(gòu)成的拉氏量出發(fā),振幅可以被寫成:T.Mannel,R.Urech. Z.Phys.C73(1775)541I4,I5,I6消失了,表明它們是小量,這個可以在將來的BESIII實驗中被檢驗.這里Gklm,G0,G2都是I1I7的函數(shù)Zhang Zhenxia10Zhang Zhenxia11可見,我們這種相移的提取,并不依賴于任何模型,是更一般的參數(shù)化方法,相比之下更準確.下面是基于BESIII的MC研究Zhang Zhenxia12樣本樣本產(chǎn)生產(chǎn)生: : 用BESIII模擬軟件產(chǎn)生一個有固定相移的 J/ +- 模擬樣本,再用上面推導的相移公式去擬合. The generated M

7、C sample is similar to the real BESII data with: , 0+phase space, f2(1270)22(1270)f(1270)fphase0|dd22ABWAABWA產(chǎn)生公式產(chǎn)生公式: : D波占48%:D波占2%,4%, 8%,20%:事例挑選事例挑選:vAll the charged tracks are required to be within the polar angle region: cos0.9vVertex cut: Z5.0cm , r1.0cmvParticle ID: 1. if P0.5, identified a

8、s pion. 2. use TOF,DE/DX, Muon id . Require all +- +- are identified out.v4-constrait kinematic fit.Mass of +-Zhang Zhenxia13 Study result (ratio of D-wave is about 45%) ( in bin of 0.5-0.51GeV +- mass spectrum) Input: 1.03radianOutput: 1.04 0.04radiancos用相移公式擬合得到的輸出值和輸入值是用相移公式擬合得到的輸出值和輸入值是一致的一致的. .

9、驗證了公式的可靠性驗證了公式的可靠性. .Blue: D-waveGreen: S-wavecos3Phase shift difference (rad)用相移公式擬合Zhang Zhenxia14D wave 4%Phase shift: 1.100.15D wave 8%Phase shift: 1.240.08D wave 20%Phase shift: 1.180.02 Study result (ratio of D-wave is about 2%, 4%,8%,20%) ( in bin of 0.5-0.51GeV +- mass spectrum)D wave 2%Phase shift: 1.520.04;1.280.08Phase shift Input: 1.17radian這里用了大約50倍的數(shù)據(jù)的統(tǒng)計量Zhang Zhen