D~0-~0 mixing sensitivity estimation at Belle II in wrong-sign decays D~0→K~+π~-π~0 via time-dependent amplitude analysis
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摘要
The sensitivity of the D~0-~0 mixing parameters x and y is estimated in the wrong-sign decay D~0→K~+π~-π~0 by time-dependent amplitude analysis. The resolution of the D~0 lifetime is essential in time-dependent Dalitz analyses. The Belle II detector, which aims to collect a total integrated luminosity of 50 ab~(-1) of data, has σ = 140 fs in Monte Carlo studies, a factor of two improvement over that of Belle and Ba Bar, so the produced Dalitz signal Monte Carlo samples are smeared with this resolution. Then a time-dependent Dalitz plot fitting is performed on these smeared samples, and the sensitivity of D~0-~0mixing parameters are σ_x = 0.057% and σ_y = 0.049%. These are about an order of magnitude improvement on current experimental results, without considering background effects.
The sensitivity of the D~0-~0 mixing parameters x and y is estimated in the wrong-sign decay D~0→K~+π~-π~0 by time-dependent amplitude analysis. The resolution of the D~0 lifetime is essential in time-dependent Dalitz analyses. The Belle II detector, which aims to collect a total integrated luminosity of 50 ab~(-1) of data, has σ = 140 fs in Monte Carlo studies, a factor of two improvement over that of Belle and Ba Bar, so the produced Dalitz signal Monte Carlo samples are smeared with this resolution. Then a time-dependent Dalitz plot fitting is performed on these smeared samples, and the sensitivity of D~0-~0mixing parameters are σ_x = 0.057% and σ_y = 0.049%. These are about an order of magnitude improvement on current experimental results, without considering background effects.
The sensitivity of the D~0-~0 mixing parameters x and y is estimated in the wrong-sign decay D~0→K~+π~-π~0 by time-dependent amplitude analysis. The resolution of the D~0 lifetime is essential in time-dependent Dalitz analyses. The Belle II detector, which aims to collect a total integrated luminosity of 50 ab~(-1) of data, has σ = 140 fs in Monte Carlo studies, a factor of two improvement over that of Belle and Ba Bar, so the produced Dalitz signal Monte Carlo samples are smeared with this resolution. Then a time-dependent Dalitz plot fitting is performed on these smeared samples, and the sensitivity of D~0-~0mixing parameters are σ_x = 0.057% and σ_y = 0.049%. These are about an order of magnitude improvement on current experimental results, without considering background effects.
引文
1 K.A.Olive et al(Particle Data Group),Chin.Phys.C,38:090001(2014)
2 Xing Zhi-Zhong,Chin.Phys.C,32:483-487(2008)
3 S.L.Glashow,J.Iliopoulos,and L.Maiani,Phys.Rev.D,2:1285(1970)
4 A.F.Falk et al,Phys.Rev.D,65:054034(2002)
5 R.Aaij et al(LHCb Collaboration),Phys.Rev.Lett.,111:241801(2013)
6 T.Aaltonen et al(CDF Collaboration),Phys.Rev.Lett.,111:231802(2013)
7 B.R.Ko et al(Belle Collaboration),Phys.Rev.Lett.,112:111801(2014)
8 R.Aaij et al(LHCb Collaboration),Phys.Rev.Lett.,116:241801(2016)
9 B.Aubert et al(Ba Bar Collaboration),Phys.Rev.Lett.,103:211801(2009)
10 Boˇstjan Golob,Karim Trabelsi,and Philip Urquijo,BELLE2-NOTE-0021
11 X.C.Tian et al(Belle Collaboration),Phys.Rev.Lett.,95:231801(2005)
12 S.Kopp et al(CLEO Collaboration),Phys.Rev.D,63:092001(2001)
13 Charles Zemach,Phys.Rev.,133:B1201(1964);Charles Zemach,Phys.Rev.,140:B109(1965)
14 T.Peng et al(Belle Collaboration),Phys.Rev.D,89:091103(R)(2014)
15 T.Abe et al KEK Report 2010-1,ar Xiv:1011.0352[physics.insdet]
16 G.Casarosa,Belle II Decay Time Resolution,Presented at the 2nd Belle II Theory Interface Platform Workshop(Krakow,April 2015)
17 D.J.Lange,Nucl.Instrum.Methods A,462:152-155(2001)
18 L.K.Li,W.B.Yan,and Z.P.Zhang,Belle Note 1381
19 M.Pelliccioni,Measurement of D~0-~0 Mixing with a TimeDependent Amplitude Analysis of D~0→K~+π~-π~0,SLAC-R-1017,Ph.D.Thesis(SLAC National Accelerator Laboratory,Stanford University,Stanford CA 94309,2009)
1)In this WS decay,there are thirteen possible resonances shown in Table 2,but referring to the Dalitz analysis of RS decay at Belle[18],ρ(1450)andρ(1700)have masses whose peaks are both outside the Dalitz plot but whose widths are so wide that their tails extend well into the region of interest.Since their fitted phase angles difference is very close to 180?,the fitting will be unable to separate them.We keep onlyρ(1700)instead of both,which is same choice as CLEO[12].We also remove K*(1680)0,because of its very small contribution to the total amplitude,with a fitting fraction less than 0.1%[18].
1)hereσis the statistical uncertainty of parameters x/r_0 or y/r_0 correspondingly.
1)These systematic uncertainties should be decreased as Belle II has a better time resolution.
2 Xing Zhi-Zhong,Chin.Phys.C,32:483-487(2008)
3 S.L.Glashow,J.Iliopoulos,and L.Maiani,Phys.Rev.D,2:1285(1970)
4 A.F.Falk et al,Phys.Rev.D,65:054034(2002)
5 R.Aaij et al(LHCb Collaboration),Phys.Rev.Lett.,111:241801(2013)
6 T.Aaltonen et al(CDF Collaboration),Phys.Rev.Lett.,111:231802(2013)
7 B.R.Ko et al(Belle Collaboration),Phys.Rev.Lett.,112:111801(2014)
8 R.Aaij et al(LHCb Collaboration),Phys.Rev.Lett.,116:241801(2016)
9 B.Aubert et al(Ba Bar Collaboration),Phys.Rev.Lett.,103:211801(2009)
10 Boˇstjan Golob,Karim Trabelsi,and Philip Urquijo,BELLE2-NOTE-0021
11 X.C.Tian et al(Belle Collaboration),Phys.Rev.Lett.,95:231801(2005)
12 S.Kopp et al(CLEO Collaboration),Phys.Rev.D,63:092001(2001)
13 Charles Zemach,Phys.Rev.,133:B1201(1964);Charles Zemach,Phys.Rev.,140:B109(1965)
14 T.Peng et al(Belle Collaboration),Phys.Rev.D,89:091103(R)(2014)
15 T.Abe et al KEK Report 2010-1,ar Xiv:1011.0352[physics.insdet]
16 G.Casarosa,Belle II Decay Time Resolution,Presented at the 2nd Belle II Theory Interface Platform Workshop(Krakow,April 2015)
17 D.J.Lange,Nucl.Instrum.Methods A,462:152-155(2001)
18 L.K.Li,W.B.Yan,and Z.P.Zhang,Belle Note 1381
19 M.Pelliccioni,Measurement of D~0-~0 Mixing with a TimeDependent Amplitude Analysis of D~0→K~+π~-π~0,SLAC-R-1017,Ph.D.Thesis(SLAC National Accelerator Laboratory,Stanford University,Stanford CA 94309,2009)
1)In this WS decay,there are thirteen possible resonances shown in Table 2,but referring to the Dalitz analysis of RS decay at Belle[18],ρ(1450)andρ(1700)have masses whose peaks are both outside the Dalitz plot but whose widths are so wide that their tails extend well into the region of interest.Since their fitted phase angles difference is very close to 180?,the fitting will be unable to separate them.We keep onlyρ(1700)instead of both,which is same choice as CLEO[12].We also remove K*(1680)0,because of its very small contribution to the total amplitude,with a fitting fraction less than 0.1%[18].
1)hereσis the statistical uncertainty of parameters x/r_0 or y/r_0 correspondingly.
1)These systematic uncertainties should be decreased as Belle II has a better time resolution.