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LHCb FCNC D0
1

.. 1 , .. 2
- , . .. ; 2 . .. E-mail: fikhen@yandex.ru.

We study the sensitivity of the LHCb detector to the rare flavor changing neutral current (FCNC) decay D0 assuming zero background. The estimate of the geometrical acceptance versus energy is presented together with calculations of the required integrated luminosity and the number of pp interactions in case of the geometrical-only and a realistic acceptance.

D0 (). , , -- [1] . Br ~10-17, ( , ) ~10-13. , . , , . . , R 3.5*10-7 [2], BaBar, Br = 1.3*10-6 [3]. , LHCb , ~10-7. ROOT ++ - () Pythia 8.125 [4]. D0->, D0- "". - s 1 14 . D0- D0. LHCb


, . s = 14 . 1. 10<<400 PZ .

. 1. . .

, , ~40%. , . 2.

. 2. .

, ,


LHC. geom =~40%. ~10-7, - . , LHCb, Pythia6.4. - 14 total = 102, D- inclusive(D0) = 2.8. D0- D0 L: N(D0)=
0 inclusive(D

)*L.

, D0 : Naccepted =
0 geom*Br(D

->)*

, Br ~10 , , D0 L=~0.9*107 -1 =~10 -1 . Ntotal=L*total=~109 pp . , (minimum-bias) , , , - . . D0-> D0->K (Br ~3.8%), D0-> (Br~0.1%) D0. , , D0 , . D0->K - . D0->K , , . : - 2track/NDF<10, PT>250 , P>2 , 2 (-) IPtrack >4. , : 2 D0,

0 inclusive(D -7

)*L.


2vertex< 2, D0 , cos()> 0.999, 2 2distance>5. , pT(D0) > 1 . - 14 LHCb -, GEANT- . 10 , D0, . 3. N(D0->K) .

. 3. D0

D0 : N(D0->K) = 1270+-70, ~ 5.6, / ~ 0.6. . , (NMC =107 ): LMC = NMC/total =~ 105-1. : Ngen(D0->K) = Br(D0->K)*inclusive(D0)*LMC= 3.8*10-2 * 2.8*105 = 10.6*103 ~ 104. , : (D0->K) = Nrec(D0->K)/Ngen(D0->K) = (1270+-70)/104 = 0.127+-0.007. ~13% ~40%. 100%


3 L=~30nb-1, , , Nevents=~3*109 . , , LHCb (~2*1010 [5]). , D0-> , , .

1. 2. 3. 4. 5.

S.L. Glashow, J. Iliopoulos, L. Maiani, Phys. Rev. D 2 (1970) 1285. G. Burdman et al., Phys. Rev. D 66 (2002) 014009. B. Aubert et al., (BaBar Collaboration), Phys. Rev. Lett. 93 (2004) 191801. T.S., S. Mrenna and P. Skands, Comput. Phys. Comm. 178 (2008) 852 [arXiv:0710.3820]. R. Antunes Nobrega et al., LHCb Computing TDR 11, CERN-LHCC-2005-019.