study of y(1s)pipi and y(1s)eta final states with lhcb detector

8/4/2019 Study of Y(1S)pipi and Y(1S)eta final states with LHCb detector

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Introduction Bottomonium spectrum MC data Search for resonances Conclusions

Study of(1S)+ and (1S) final stateswith LHCb detector

Vitaly Vorobyev, Summer Student.Supervisor: Anton Poluektov

Novosibirsk State University,Budker Institute of Nuclear Physics

August 24, 2011

1 / 10 Vitaly Vorobyev, Summer Student. Supervisor: Anton Poluektov Study of(1S)+ and (1S) final states with LHCb detector
http://find/http://goback/


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Contents

1 IntroductionRecent observation of Z

()b by Belle

Other possible states

2 Bottomonium spectrum

3 MC data

4 Search for resonancesFinal state (1S)+

Final state (1S)

5 Conclusions

http://find/


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Recent observation ofZb

by Belle Other possible states

Recent observation ofZ()b by Belle

Anomalously high rates for (5S) hb(1P, 2P)+ decays [1]

Recently discovered resonances Z()b have explained anomality. [2]

Belle results

Distributions of missing mass associated with for

(5S) (2S) (left), (5S) hb(1P) (center) and(5S) hb(2P) (right): [2]

[1] Belle Collaboration, arXiv:1103.3419v1 [hep-ex]

[2] I. Adachi et al. (Belle Collaboration), arXiv:1105.4583v1 [hep-ex]3 / 10 Vitaly Vorobyev, Summer Student. Supervisor: Anton Poluektov Study of(1S)+ and (1S) final states with LHCb detector


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Introduction Bottomonium spectrum MC data Search for resonances ConclusionsRecent observation ofZb

by Belle Other possible states

Other possible states

Other bottomonium-like states? Yes! [3]

Z()b

IG(JP) = 1+(1+)

Y()b

Y()b are I = 0 counterparts of isotriplet Z

()b with J

PC = 1+

Y()b are not accesible from the (5S) decays:

(5S) Y()b

is suppressed due to isospin conservation;

(5S) Y()b

is kinematically forbidden.

Could be visible in LHCb experiment:S-wave: (1S, 2S), (1S)

P-wave: (1S)

[3] A.E. Bondar, A. Garmash, A.I. Milstein, R. Mizuk, M.B. Voloshin,

arXiv:1105.4473v2 [hep-ph]4 / 10 Vitaly Vorobyev, Summer Student. Supervisor: Anton Poluektov Study of(1S)+ and (1S) final states with LHCb detector

I d i B i MC d S h f C l i


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(+) mass spectrum

337 pb1, 2011 data.

Stripping 13:FullDSTDiMuonDiMuonHighMassLine

Selections

pt() > 500 MeV

Parameterization

Signal: Crystal Ball function

Background: 2nd order Chebychev

polynomial.

Parameter (1S) (2S) (3S)Mass (MeV) 9441.4 0.1 10003.3 0.3 10334.2 0.5

Width (MeV) 43.1 0.1 45.6 0.3 47.2 0.5Number of events (103) 233.2 0.7 55.7 0.4 27.7 0.3


I t d ti B tt i t MC d t S h f C l i


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Generator level MC

Generator level MC for(2S) (1S) and(2S) (1S)(+0)

pt of pions is very low!

pt() from (2S) (1S)

pt() from (2S) (1S)

pt(0) from (2S) (1S)



Final state (1S)+ Final state (1S)


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Introduction Bottomonium spectrum MC data Search for resonances ConclusionsFinal state (1S)+ Final state (1S)

Final state (1S)+

Stripping

FullDSTDiMuonDiMounHighMassLinePions

pt() > 150 MeVpt(

+) +pt() > 400 MeV

2(IP)/n.d.f < 9

logPID(K ) < 5Muons

pt() > 1000 MeVpt(

+) +pt() > 7000 MeV

2(IP)/n.d.f < 9logPID( ) > 1

Upsilon

|m (+) m ((1S))| < 130 MeVKinematics

dtf2/n.d.f < 4pt ((1S)

+) > 3000 MeV

(2S) (1S)+

Efficiency

= nrecntot

0.2%





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Final state (1S)+

(2S) (1S)+

2

/n.d.f. = 87.2/54

(3S) (1S)+

2

/n.d.f. = 67.2/57

Y()b (1S)

+

2

/n.d.f. = 63.6/57

Parameterization: Gaussian + 2nd order Chebychev polynomial.

(2S) (1S)+ signal:

ns = (1654 165)m = (10022.4 0.3) MeV = (3.0 0.4) MeV





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(2S) J/ decay

Pions

pt(0) > 100 MeVpt(

+) +pt() +pt(

0) > 300 MeV2(IP)/n.d.f < 9

logPID(K ) < 5Muons

2

(IP)/n.d.f < 9logPID( ) > 1J/

|m (+) m (J/)| < 70 MeVKinematics

pt ((1S)+) > 3000 MeV

Only 35 pb1 is treated.

Probably, one cant see(2S) (1S) signal with presentdata.




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t oduct o otto o u spect u C data Sea c o eso a ces Co c us o s

Conclusions

Conclusions

1 Production of (1S)X in the primary vertex makes study ofbottomonium-like resonances difficult.

2 Low pt of signal pions makes the situation even worse:

many background pions with low pt;low efficiency for low pt pions.

3 Maybe, one will be able to obtain interesting results with muchlarger statistics.

Thank you!Contacts: [email protected] or [email protected]

mailto:[email protected]:[email protected]:[email protected]:[email protected]://find/

study of y(1s)pipi and y(1s)eta final states with lhcb detector

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