New Results on 3770 and D Mesons Production

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New Results on (3770) and D Mesons Production and Decays From BES Gang RONG

New Results on (3770) and D Mesons Production and Decays From BES Gang RONG (for BES Collaboration) Presented by Yi-Fang Wang Charm 07 Cornell University, August 4 -8 2007 1

Outline u Introduction u Inclusive decays of D Mesons u Measurements of R u

Outline u Introduction u Inclusive decays of D Mesons u Measurements of R u Parameters of (3770) u B[ (3770) non-DD] and Search for Charmless decays of (3770) u Summary 2

Introduction BESII (3770) data sample of -1 v about 17. 3 pb data taken

Introduction BESII (3770) data sample of -1 v about 17. 3 pb data taken at 3. 773 Ge. V about 33 pb-1 v about 7 pb-1 data taken from 3. 768 Ge. V to 3. 778 Ge. V v about 8 pb-1 data taken from 3. 665 to 3. 878 Ge. V Data Samples • about 6. 5 pb-1 data taken at 3. 650 Ge. V • about 1 pb-1 data taken at 3. 665 Ge. V pb-1 World (3770) Samples (pb-1) 3 (by summer, 2005)

D- and D 0 tags Double tag analysis Absolute measurements 4

D- and D 0 tags Double tag analysis Absolute measurements 4

D +X Dtag De+ P+ D K+ Singly tagged D sample π– π– D+

D +X Dtag De+ P+ D K+ Singly tagged D sample π– π– D+ With the singly tagged D sample, we can do some absolute measurements of D decays on the side recoiling against the tags. PT e- 0. 52 -0. 62 Ge. V 0. 62 -0. 72 Ge. V X=any particles 0. 72 -0. 82 Ge. V 0. 82 -0. 92 Ge. V P+ is any charged particle ( , e, π and K) 0. 92 -1. 02 Ge. V Nμ obs m. Knπ(Dtag) 5

D +X μtrue etrue Ktrue Nobs =observed particle I; Ntrue i i= true particle

D +X μtrue etrue Ktrue Nobs =observed particle I; Ntrue i i= true particle i ARGUS 6. 0± 0. 7± 1. 2 - CHORUS 6. 5± 1. 2± 0. 3 - BES-II 6. 8± 1. 5± 0. 6 17. 6± 0. 7± 1. 3 PDG 6. 5± 0. 7 16. 1± 0. 4 πtrue εim= ratio of a particle “i” to be identified as “m” First measurements PDG 6

D e+X and D KX B(D e+X) and B(D KX) CLEO-c 6. 46± 0.

D e+X and D KX B(D e+X) and B(D KX) CLEO-c 6. 46± 0. 17± 0. 13 16. 13± 0. 20± 0. 33 Mark. III 7. 5± 1. 1± 0. 4 17. 0± 1. 9± 0. 7 BES-II 6. 3± 0. 7± 0. 4 15. 2± 1. 0± 0. 7 PDG 2007 6. 55± 0. 17 16. 1± 0. 4 Preliminary Comparison of Results BES-II 24. 7± 1. 3± 1. 2 15. 2± 1. 0± 0. 7 57. 8± 1. 6± 3. 4 3. 5± 0. 7± 0. 3 PDG 2007 27. 5± 2. 4 5. 5± 1. 6 53± 4 3. 4+0. 6 -0. 4 7

The quantity R u. Why are we interested in R(s) ? • Vacuum polarization

The quantity R u. Why are we interested in R(s) ? • Vacuum polarization correction needs the R(s) values, which plays an important role in the precision test of the Standard Model. • For evaluation of the electromagnetic coupling at the Z mass scale, • For determination of of the muon. • Evaluate • Non-DD decays of (3770) • important in open charm region for the understanding of 1 -resonance production, for searching for new states, and for studying dynamics … 8

The quantity R u (3770) production & decays It is believed to be a

The quantity R u (3770) production & decays It is believed to be a mixture of and states of system. It is thought to decay almost entirely to pure DDbar. Before BES-II & CLEO-c, previously published data indicate that more than about 35% of (3770) does not decay to DD-bar ? This conflicts with theoretical prediction. 9

The quantity R u. New Measurements Recently BES and CLEO-c measured the DD and

The quantity R u. New Measurements Recently BES and CLEO-c measured the DD and (3770) production at 3. 773 Ge. V based on the data taken below DD threshold and at 3. 773 Ge. V. To uncover the puzzle, a better way is to make cross section scan A better way to measure the cross sections, the widths of the resonance and the DD branching fractions of (3770) is to analyze the line-shapes of (3770), (3686) and DD production simultaneously. BES made several fine cross section scans covering both the (3686) and (3770) to measure the resonance parameters, branching fractions and search for non-DD decays … 10

The quantity R The Previously Measured quantity R Including all hadrons Precision measurement of

The quantity R The Previously Measured quantity R Including all hadrons Precision measurement of the cross sections in this region 11

The quantity R Definition of different R above cc-bar threshold below cc-bar threshold hadrons

The quantity R Definition of different R above cc-bar threshold below cc-bar threshold hadrons [where q is the light (u, d, s) quarks] Ruds Evaluate Rhad(s)=Ruds(c)(s)+ΣRres, i(s), Rres, i(s) is R values due to all 1-- resonances decay to hadrons except Ψ(3770). hadrons Rhad calculate 12

The quantity R ISR corrections Effective c. m. energy Moninal c. m. energy Kuraev

The quantity R ISR corrections Effective c. m. energy Moninal c. m. energy Kuraev & Fadin the electron equivalent radiator thickness 13

The quantity R Vacuum polarization correction Vacuum polarization change the photon propagator results in

The quantity R Vacuum polarization correction Vacuum polarization change the photon propagator results in Radiative correction factor 14

The quantity R Results PRL 97, 262001 (2006) above cc-bar threshold below cc-bar threshold

The quantity R Results PRL 97, 262001 (2006) above cc-bar threshold below cc-bar threshold Ruds = 2. 141± 0. 025± 0. 085 Below DD-bar threshold Rp. QCDuds = 2. 15± 0. 03 Sources ΔSYS (%) Luminosity 1. 8 Hadron selection 2. 5 M. C. modeling 2. 0 ISR 1. 5 Ψ(3770) resonance parameters 2. 7 Total (off Ψ(3770) region) 3. 9 Total (within Ψ(3770) region) 4. 9 15

The quantity R Comparison of R measurements from different experiments PLB 641 (2006) 145

The quantity R Comparison of R measurements from different experiments PLB 641 (2006) 145 16

Resonance Parameters of (3770) New measurements 68 energy points Dec. 2003 data 17 The

Resonance Parameters of (3770) New measurements 68 energy points Dec. 2003 data 17 The paper is being in press (PLB)

Resonance Parameters of (3770) New measurements Comparison with those measured by other experiments prd[e+e-

Resonance Parameters of (3770) New measurements Comparison with those measured by other experiments prd[e+e- (3770)][nb] obs[e+e- (3770)][nb] Experiment This work [Dec. 2003 data] 10. 0 0. 3 0. 5 7. 2 0. 4 BES [PRL 97(2006)121801] 9. 6 0. 7 0. 4 6. 9 0. 5 0. 3 MARKII 9. 3 1. 4 M (3770)(Me. V) tot (3770)(Me. V) ee (3770)(e. V) Note 3772. 4 0. 3 28. 5 1. 2 0. 2 277 11 13 PLB in press 3772. 2 0. 7 0. 3 26. 9 2. 4 0. 3 251 26 11 PRL 97(2006)121801 Experiment PLB in press B[ (3770) e+e-][ 10 -5] 0. 97 0. 03 0. 05 [Dec. 2003 data] PRL 97(2006)121801 PDG 0. 93 0. 06 0. 03 1. 05 0. 14 [Dec. 2003 data] Ruds=2. 121 0. 023 0. 084 18

Resonance Parameters of (3770) What about World Average Comparison of measurements of the cross

Resonance Parameters of (3770) What about World Average Comparison of measurements of the cross section for (3770) production Leptonic branching fraction PRL 97 (2006) 121801 Preliminary ! PRL 97 (2006) 121801 PDG 04 19

B[ (3770) non-DD] PLB 641 (2006) 145 Determined from analysis of R values and

B[ (3770) non-DD] PLB 641 (2006) 145 Determined from analysis of R values and DD-bar cross sections PRL 97 (2006) 121801 Obtained by fitting to the inclusive hadron and the DD-bar production cross sections simultaneously. PDG 07 20

Search for Charmless Decays of (3770) Mode 3. 773[pb] 3. 650[pb] Bup[ 10 -3]

Search for Charmless Decays of (3770) Mode 3. 773[pb] 3. 650[pb] Bup[ 10 -3] 0 <3. 5 <8. 9 <0. 5 <12. 6 <18. 0 1. 9 2( + -) 173. 7 8. 4 177. 7 13. 3 18. 8 4. 8 K+K- + - 131. 7 10. 1 14. 1 161. 7 17. 9 17. 1 4. 8 + - <11. 1 <22. 9 1. 6 2(K+K) 19. 9 3. 6 2. 1 24. 1 6. 5 2. 6 1. 7 K+K 15. 8 5. 1 1. 8 17. 4 9. 2 2. 0 2. 4 ppbar + - 33. 2 3. 4 3. 8 42. 1 6. 1 4. 8 1. 6 ppbar. K+K 7. 1 2. 0 0. 8 6. 1 3. 1 0. 7 1. 1 ppbar <5. 8 <9. 1 0. 9 3( + -) 236. 7 14. 7 33. 4 234. 9 23. 8 33. 1 9. 1 2( + -) 153. 7 40. 1 18. 4 86. 6 40. 3 10. 4 24. 3 2( + -) 0 80. 9 13. 9 10. 0 124. 3 21. 7 14. 9 6. 2 K+K- + - 0 171. 6 26. 0 20. 9 222. 8 37. 7 27. 2 11. 1 2(K+K) 0 18. 1 7. 7 2. 1 <23. 0 4. 6 ppbar 0 10. 1 2. 2 1. 0 9. 2 3. 4 1. 0 1. 2 ppbar + - 0 53. 1 9. 2 6. 8 29. 0 11. 1 3. 7 7. 3 3( + -) 0 105. 8 34. 4 16. 9 126. 6 47. 1 19. 2 13. 7 Search for Charmless decays of (3770) We have searched for more than 40 modes for the light hadron decays. PLB 650(2007)111 21

Search for Charmless Decays of (3770) Preliminary Results Mode K+K-2( + -) 3. 773[pb]

Search for Charmless Decays of (3770) Preliminary Results Mode K+K-2( + -) 3. 773[pb] 3. 650[pb] 168. 0 18. 2 23. 164. 9 30. 3 23. 7 2 Bup[ 10 -3] <10. 3 2(K+K-) + - 11. 9 5. 8 1. 7 <49. 1 <3. 2 ppbar 2( + -) 23. 5 5. 0 3. 5 22. 8 8. 4 3. 4 <2. 6 4( + -) 131. 8 19. 5 23. 6 76. 2 24. 4 13. 9 <16. 7 K+K-2( + -) 0 231. 5 63. 6 37. 5 <375. 2 <52. 0 4( + -) 0 <206. 9 <119. 4 <30. 6 0 + - 111. 9 13. 1 113. 6 21. 3 13. 1 <6. 9 0 K+K- 34. 2 11. 5 4. 4 57. 6 17. 9 6. 3 <5. 0 0 ppbar 13. 1 3. 2 1. 8 17. 7 6. 2 2. 8 <1. 7 K*0 K- + 94. 7 15. 5 10. 4 85. 5 26. 3 14. 4 Search for lighthadron decays of (3770) <9. 7 bar <2. 5 <6. 1 <0. 4 bar + - <26. 7 <42. 9 <4. 4 22

Search for Charmless Decays of (3770) Search for light-hadron decays of (3770) Mode 3.

Search for Charmless Decays of (3770) Search for light-hadron decays of (3770) Mode 3. 773[pb] 3. 650[pb] Bup[ 10 -3] + - <37. 1 <50. 8 5. 5 K+K- <44. 4 <53. 2 6. 6 ppbar <20. 3 <30. 9 3. 0 + - 0 <25. 5 <66. 7 3. 8 K*0 K- + 0 116. 3 32. 7 20. 0 128. 1 59. 5 17. 9 16. 3 K*+K- + - 173. 9 73. 3 26. 1 189. 0 116. 3 28. 2 32. 4 K+K- 0 0 <5. 6 47. 6 33. 4 10. 7 0. 8 K+K- + - 94. 2 31. 6 11. 7 141. 9 53. 3 19. 7 14. 6 bar 0 <7. 9 <21. 4 1. 2 Preliminary Results Upper limits are set at 90% CL We searched for (3770) light hadrons over 40 channels, but no significant signals were found. This does not mean that (3770) does not decay into light hadrons. To extract the branching fractions for (3770) light hadrons from the observed cross sections, one need to make finer cross section scan covering 23 both (3686) and (3770) with larger data samples (BES-III can do this well).

SUMMARY • Inclusive decays of D mesons Measured BF(D+ mu+ X)=(17. 6+-2. 7+-1. 3)%

SUMMARY • Inclusive decays of D mesons Measured BF(D+ mu+ X)=(17. 6+-2. 7+-1. 3)% for the first time Measured BF(D+ K- X)=(24. 7+-1. 3+-1. 2)% Measured BF(D+ K+ X)=(6. 1+-0. 9+-0. 4)% Measured BF(D 0 K- X)=(57. 8+-1. 6+-3. 4)% Improved measurements • R value Improved measurements of R in the range from 3. 65 to 3. 88 Ge. V Measured Ruds = 2. 121+-0. 023+-0. 085 Measured Ruds(c)+ (3770) for the first time • (3770) parameters Precisely measured M (3770) =3772. 3+-0. 5 Me. V; Γtot=28. 5+-1. 2 Me. V; Γee=277+-16 e. V Precisely measured BF( e+e-)=(0. 97+-0. 08+-0. 05)x 10 -5 σobs (3770) = 7. 15+-0. 25 nb [combined two measurements] 24

SUMMARY Combined 49 energy point cross section scan results and 3 energy point cross

SUMMARY Combined 49 energy point cross section scan results and 3 energy point cross section results (inclusive hadron and DD-bar cross sections) • BF[ (3770) non-DDbar] Measured BF[ (3770) non-DDbar] = (15+-5)% Measured BF[ (3770) DDbar] = (85+-5)% PDG 07 [BES] • Light hadron decays of (3770) No significant signals for (3770) light hadron were found in about 40 channels. • How to solve this problem ? Finer cross section scan over (3686) and (3770) to measure the cross sections for exclusive modes and fitting the cross sections to extract out the branching fractions (My comment only !) 25

Thank You! 26

Thank You! 26

Backup slides 27

Backup slides 27

Comparison with those measured by CLEO-c BES-II CLEO-c (hep-ex/0512038); PRL 96 (2006) 092002 Based

Comparison with those measured by CLEO-c BES-II CLEO-c (hep-ex/0512038); PRL 96 (2006) 092002 Based on analysis of inclusive hadron and DD-bar cross section scan data. PLB 141 (2006) 145 Actually, considering the errors, the two results are not in contradiction. 28

Comparison with those measured by CLEO-c BES-II CLEO-c Assuming that there are interference between

Comparison with those measured by CLEO-c BES-II CLEO-c Assuming that there are interference between the two amplitudes of continuum and resonance Based on measured R values. Method: BES measured near DD-bar threshold and R at 3. 773 Ge. V with traditional method, then calculate the Born order cross section for (3770) production. By comparing the cross sections for DD-bar and (3770) production, BES obtained the branching fraction. BES used an ISR generator to simulate the decay e+e- hadrons and obtain the efficiency for e+e- hadrons. Use parameter Method: CLEO-c directly count the number of hadronic events observed at 3. 773 Ge. V, and subtract the backgrounds from J/ , (2 S) radiative tails and continuum QED background. CLEO-c used the efficiency for the decay (3770) J/ π+ π- to estimate the efficiency for e+e- hadrons. Use parameter 29

Comparison with those measured by CLEO-c Discussion BES-II Method: CLEO-c did not consider the

Comparison with those measured by CLEO-c Discussion BES-II Method: CLEO-c did not consider the difference of ISR if we use to calculate the ISR & vacuum polarization correction factor, & vacuum polarization corrections for continuum hadron production at the two and assuming that there are interference between the two amplitudes of the continuum energy points (3. 671 Ge. V and 3. 773 Ge. V) when and the resonance, we would obtain subtracting background at 3. 773 Ge. V. PRL 97 (2006) 121801 30