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Recent results from the HERA-B experiment
Roberto Spighi, INFN Bologna Italy For the HERA-B Collaboration

The XVIIIth International Workshop High Energy Physics and Quantum Field Theory 17-23 june 2004, St. Petersburg

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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Outline Outline
Main physics studies at HERA-B Main physics studies at HERA-B Detector Detector Physics topics addressed: Physics topics addressed: Production of: Production of: Open and hidden Charm Open and hidden Charm Open and hidden Beauty Open and hidden Beauty FCNC process FCNC process Hard photons Hard photons Strangeness production Strangeness production Pentaquark search Pentaquark search Summary Summary
QFTHEP, 17-23 June 2004

Disclaimer: All results are preliminary
Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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Main physics studies at HERA-B Main physics studies at HERA-B
Do(+,*+),, J/,, (2S), cc Do(+,*+) J/ (2S), pT ,, xFF and decay angle pT x and decay angle A-dependence A-dependence Charm production Strangeness production Koos,,,, ,, K**, Ks K, hyperons hyperons ·· ·· ·· ~ ~ ~ ~ ~ ~ Beauty production Pentaquark search search production production ¯ bb, (1-3S) bb, (1-3S)

Hard photons , 00, , ,

++,, ---- + c.c. + c.c.

1150 ·· 1066 dilepton triggered events ~300 k J/ 50 10 dilepton triggered events ~300 k J/ 210 ·· 1066 minimum bias events 210 10 minimum bias events 35 ·· 1066 hard photon triggered events 35 10 hard photon triggered events
Roberto Spighi (HERA-B coll.) Recent results from HERA-B

QFTHEP, 17-23 June 2004

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Physics motivation Physics motivation
· Test of QCD predictions: NRQCD confirmed at high energy (CDF s =1.8 TeV) and large pT, no conclusive results at lower energy · Investigation of nuclear effects for correct interpretation of results from ultra relativistic heavy ion collisions (QGP) charm production beauty production

· no (or very few) results in the negative xF range · few results on the J/, (2S) polarization · contradictory results on R(c/J/) · (bb): only two other measurements (E771, E789) with large uncertainties and poor compatibility · (): testing ground for the theoretical models
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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Charmonium Production in media Charmonium Production in media
Investigation of nuclear effects Further physics for production in media ·Nuclear effect in initial and final state ·Initial state: ·Shadowing, parton energy loss, transverse momentum broadening ( dependence on A) ·Final state: ·Nuclear absorption (dependence on xF), Comover suppression Necessary to study the charmonium differential distributions Important baseline measurements for QGP study HERA-B is in the ideal condition to study these effects
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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The Hera-B Detector The Hera-B Detector

Electron beam

· Fixed target detector at HERA (DESY) · 920 GeV/c proton beam (s = 41.6 GeV)

-- IR 5 ­ 10 MHz

· High angular coverage (15-220 mrad in bending plane) · High resolution spectrometer -- very good particle ID for (e, µ, , K, p)
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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Target system Target system
8 wire targets (C, Al, Ti, W, Pd) in proton halo

Station 1 Al C

Station 2 Pd Ti
Proton Beam

W Ti W C
Target materials as inJan 2003

Different targets (range A[12:184]) can be used simultaneously A-dependence measurements control of systematic errors Events from different wires can be easily separated
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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The vertex detector The vertex detector
Silicon Vertex Detector
· 7 superlayers of silicon microstrips · High primary vertex resolution (x ~ y ~ 50 µm, z ~ 450 µm)
10 3 10 2 10 1 -1 -0.5 0 0.5 1

Vertex-wire distance
10 3 10 2 10 1 -0.05 -0.025 0
(cm)

0.025 0.05

vz

(cm)

vx

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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Main tracking system Main tracking system
The world largest honeycomb tracker

Track efficiency ~ 90-95% Momentum resolution ~ 1.5%
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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Particle Identification (RICH) Particle Identification (RICH)
Example: reconstruction

Pion/kaon sep : 10< p <60 GeV Kaon/proton sep: 20< p <90 GeV

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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Particle Identification (Ecal) Particle Identification (Ecal)
E p

=

cluster energy on Ecal momentum from tracker
250 200

Bremsstrahlung tag
pN magnet

ECAL

150

µ = 0.99 = 0.06

e


X

X ~ 1/E

e

100

50

Z
0.8 0.85 0.9 0.95 1 1.05 1.1 1.15 1.2

0

E/p

Entries/(0.033 GeV/c2)

Entries/(0.033 GeV/c2)

x 10 2

Entries/(0.033 GeV/c )

1800 1600 1400 1200 1000 800 600 400 200 0 2.5 3 3.5 4 4.5

2

5000 4000 3000 2000 1000 0

12000 10000 8000 6000

51k J/

25k J/

E/p & opt 4000 cut
2000

ee Invariant mass

GeV/c2

5

+ 1-2 BR
2.5 3 3.5 4 4.5 5

0

ee Invariant mass

GeV/c

2

2.5

3

3.5

4

4.5

ee Invariant mass

GeV/c2

5

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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Particle Identification (Muon) Particle Identification (Muon)
drift tubes + iron absorber 4 superlayers

MB events
Without likelihood request

Entries/(0.010 GeV/c )

2

4500 4000 3500 3000 2500 2000 1500 1000 500 0 2.4 2.6

µµ Invariant mass

2.8

3

3.2

3.4

3.6

GeV/c2

3.8

4

.

With likelihood request J/ peak is visible

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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Dilepton trigger system Dilepton trigger system
on average ½ interaction per proton bunch 5 MHz Pretriggers: ECAL cluster or MUON hit coincidence FLT: track-based hardware trigger (track finding behind magnet) SLT (PC farm): track finding, SVD, vertexing 20 kHz Dilepton trigger: · at least 2 pretrigger seeds · coincidence with at least 1 FLT track · coincidence with at least 2 SLT tracks

100 Hz 4LT (PC farm): online reconstruction

total suppression factor 1:50000 1000-1500 J/ h-1

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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Dilepton data analysis Dilepton data analysis - charmonium production - charmonium production - J/, cc, '' - J/, , - A-dependence - A-dependence o - D_oµ++µ-- (FCNC process) - D µ µ (FCNC process) - bb production - bb production - - - Low mass studies ((, /)) - Low mass studies , / - Exotics production - Exotics production
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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Dielectron spectra Dielectron spectra
Entries/(0.033 GeV/c2)
12000 10000 8000 6000 4000 2000 0 2.5 3 3.5 4 4.5 5

Total e+e- statistics: ~ 108,000 J/ = 64 MeV/c ~ 1600 (2S)
2

J/

/
ee Invariant mass GeV/c
2



(2S)

Entries/(0.033 GeV/c )

2

1200 1000 800 600 400 200 0

,



Low mass range
0.4 0.6 0.8 1

ee Invariant mass

GeV/c2

1.2

.

Signals clearly visible: · various e-ID cuts applied to reduce high bkg level
Recent results from HERA-B

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

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Dimuon spectra Dimuon spectra
~ 177,000 J/ = 44 MeV/c2
Entries per 11.1 MeV/c

800 600 400 200 0.4 0.6 0.8
,



2

~ 3000 (2S)

Low mass range
M ( µ+µ-) [GeV/ c 2 ]

1.0 1.2

Signal clearly visible, low bkg situation · 2 independent analyses · high statistics & quality in both samples
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.)

(1S)

(2/3S)

High mass range
Recent results from HERA-B

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pT differential distribution of J/ pT differential distribution of J/
2

10 4

15% of e+e sample

-

pT J/ transverse momentum Arbitrary scale normalization
d 1 2 dpT 35 + 256
2

dN/dpT

10

3

p

2 T

10 2

pT

2



-6

HERA-B range pT < 4.5 GeV/c
1 2 3 4 5

10 0

pT

GeV/c

Target

electron

muon

stat. err.

Preliminary results for (GeV/c)

C W

1.24 1.29

1.22 1.30

0.01 0.01

Good agreement between e+e-/µ+µ- analyses
Exp. E771 E789
QFTHEP, 17-23 June 2004

wide pT range
Range (GeV/c) < 3.4 < 2.6

A dependence?
(GeV/c) 1.20 ± 0.01 1.29 ± 0.01

Interaction & p-momentum p-Si @ 800 GeV p-Au @ 800 GeV

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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xFF differential distribution of J/ x differential distribution of J/
dN/dxF
10 4

xF --> J/ Feynman-x Arbitrary scale normalization d dx
F

(1-|xF|)

c

10 3

15% of e+e sample
-0.4 -0.3 -0.2 -0.1 0 0.1

-

HERA-B range -0.35 < xF < 0.15
0.2

xF

.

Preliminary results for c [5:6.5] ± 0.2
Range 0.0< xF< 0.6 0.30< xF <0.95 -0.05 < xF <0.25 0.30 < xF < 0.95 -0.035 < xF < 0.135 c 6.18 ± 0.16 5.32 ± 0.05 6.54 ± 0.23 5.21 ± 0.04 4.91 ± 0.18

Exp. E672/E706 E789 E771 E789 E789

Interaction & p-momentum p-Be @ 800 GeV p-Be @ 800 GeV p-Si @ 800 GeV p-Cu @ 800 GeV p-Au @ 800 GeV

Not clear panorama. Now negative xF range accessible with HERA-B.
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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and c dependence on s and c dependence on s
p (GeV/c) (GeV/c) T
1.6 1.4 1.2 1 0.8 0 10 20 30
Be, AG H2, NA3 Pt, NA3 (C,Cu,W), E444 Be, E705 Be, E672/706 Si, E771 Au, E789 p, ISR p, ISR p, ISR C, HERA-B W, HERA-B

phenomenologic = A + B s
Fermilab-pub-91/62-E(1991) (E672/706 Coll)

PRELIMINARY
40 50

A=0.813 ± 0.014 GeV/c B=0.0105 ± 0.0004c-1
s (GeV)
60 70 s (GeV)

xF exponent c

8 7 6 5 4 3 2 1 0 0

Be, SIGMA Be, AG C, E331 Sn, E331 (C,Cu,W), E444 Be, E705 Fe, E379 Be, E672/706 Si, E771 Au, E789 Be, E789

HERA-B

phenomenologic c = D/(1 + E /s)
Fermilab-pub-91/62-E(1991) (E672/706 Coll)

PRELIMINARY
5 10 15 20 25 30 35

D=8.80 ± 0.41 E=23.9 ± 2.7 GeV
s (GeV)
40 45 s (GeV)

HERA-B precision competitive with previous results
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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cos differential distribution of J/ cos differential distribution of J/
dN/dcos
20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 -1 -0.8 -0.6 -0.4 -0.2 0 0.2

is the Gottfried-Jackson decay angle

d dcos
= (0,1,-1)
1

= (1 + cos2 )

J/ polarization described by parameter
15% of e+e sample
0.4
-

(no, trans., long.) polarization

cos

0.6

0.8

.



HERA-B variation range
Exp. E379 E672/E706 E672/E706 E771 p-Fe @ 400 GeV p-Be @ 530 GeV p-Be @ 800 GeV p-Si @ 800 GeV

[-0.5,0.1] ±0.1

0.16 ± 0.08 0.01 ± 0.15 -0.11 ± 0.15 -0.09 ± 0.12

1.5 1 0.5 0

Important tests for models

Interaction & p-momentum

-0.5 -1 -1.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

pT

GeV/c

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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A dependence of J/ production A dependence of J/ production
Parameterization of cross section:



pA

=

pN

A ; = N /( L )

Determine from two different targets:

N W LC C ln = ln ( AW / AC ) N C LW W 1
stat. errors only

· C (A=12.0) and W (A=183.8)
· 25% of full e+e- sample · Ratio of luminosities under investigation norm. to E866

E866 with Be, Fe and W

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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A dependence of J/ A dependence of J/
Expected stat. error for full data muon sample: c all J/ direct J/ NRQCD pred.: R. Vogt
Nucl. Phys. A700 (2002) 539

'

HERA-B range

BCKT pred.: K.G. Boreskov, A.B. Kaidalov
JETP. Lett. 77 (2003) 599

all J/

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

(22)


'' / J/ production ratio / J/ production ratio
Measurement of
Br( Br(J /
+- +-

N J/ ) ( ) = ) (J / ) NJ/



·



efficiency
4 3.5 3 2.5 2 1.5 1 0.5 0
4 3.5 3 2.5 2 1.5 1 0.5 0 1 10

· Br branch. ratio
B() / B(J/) (%)

Br·(') Br·(J/)

=

(1.6 ± 0.2stat)% C (1.8 ± 0.4stat)% W

s

from electron analysis
Experimental situation
(E288, E331, ISR, E444, E705, E537, E789, E771, NA51, NA38, NA50)

HERA-B (not fitted)

(compatible results from muons)
B() / B(J/) (%)

10

20

30

40

50

60 sqrt(s) (GeV)

A

Competitive measurement from HERA-B
QFTHEP, 17-23 June 2004

HERA-B (not fitted)
10 target atomic weight (A)
2

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

(23)


'' differential distributions differential distributions
~ 1.4 stat err 0.1 GeV/c
10
2 d()/dpT [nb GeV-2c2/nucleon]
2

d/dp

T

2

d/dx
d()/dxF [nb/nucleon]
10
2

c' = [4:5.5] ± 0.7
F

E789 E771 10 HERA-B
(arbitrarily normalized)

1

10

-1

E789 10 E771 HERA-B
(arbitrarily normalized)

10

-2

0

1

2

3

4

5

6

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

pT [GeV/c]

x

F

HERA-B compatible with previous results Comparable precision First measurement in the negative xF range !
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.)

E789: 800 GeV/c p-Au E771: 800 Gev/c p-Si
Recent results from HERA-B

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cc to J/ production ratio to J/ production ratio
No distinction between c1 and c2 (M = 46 MeV/c2) c0 neglected due to small Br
c

J/

µ+µ- and

e+e-

R



c

=
P1 P2 P3 P4


i =1

2

1 0.4


( ci ) Br ( ci J / ) ( J / )
600
190.3 0.5706E-02 0.5224E-02 0.6846E-04
55.15 P1 P2 P3 P4

J / N (c ) = N ( J / ) J /
R
c

5000 4000 3000 2000 1000 0

55.15 / 45 1281. 0.4190 0.3592E-01 0.2001E-01

500 400 300 200 100 0 -100 -200

/ 45 1281. 0.4190 0.3592E-01 0.2001E-01

190.3 0.5706E-02 0.5224E-02 0.6846E-04

= 0.21 ±0.05

Systematic studies ongoing
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

1

M (GeV/c2)
QFTHEP, 17-23 June 2004

In 15% of µµ sample 1300 c expected ~15 k for full sample
Recent results from HERA-B

Roberto Spighi (HERA-B coll.)

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Rc experimental situation and expectations R c experimental situation and expectations
Exp. E610 E705 E771 Interaction & s p-Be @ 19.4-21.7 GeV p-Li @ 23.8 GeV p-Si @ 38.8 GeV R(c) 0.47 ± 0.23 0.30 ± 0.04 0.74 ± 0.17
c

No clear experimental panorama
1

Theoretical expectations
A pA pA (HERA-B)
N pN

R

c

= 0.21 ±0.05

R
0.8 0.6 0.4 0.2

R(c) = 0.32±0.06±0.04 Results of 2000 (Phys.Lett. B561(2003) 61)
N(c) = 370±74 (both µ+µ-, e+e-)

CSM

average

N pN

NRQCD

0

10

20

30

40

50

60

HERA-B results agree with NRQCD expectations Final precision
QFTHEP, 17-23 June 2004

70 80 s (GeV) s (GeV)

more stringent tests

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

(26)


Dooµ+µ- µ+µ- D Search of FCNC in the decay BR(Doµ+µ-):
expected BR for Standard Model ~ 10-19 supersimmetric model enhances to ~ 10-7 18 evt 3 evt 6 evt

Upper limit on the branching ratio: BR(Doµ+µ-) < 2.0 x 10-6 (90% cl) hep-ex/0405059 Submitted to Phys Lett B Previous limit: CDF: BR(Doµ+µ-) < 2.5 x10 Currently best upper limit
-6

Phys.Rev. D 68 (2003) 091101

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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Open beauty production Open beauty production
pA bb+ X, bJ/+Y Select detached vertex to separate B (decay length ~7 mm) from J/
Dilepton vertex resolution 0.5 mm
(e+) (e-)



bb

=

J /

n nJ

B /



R

z B

1 Br (b b J / )

Results of 2000:
Eur. Phys.J. C26(2003) 345:

( bb ) = 32

e+e- = 8 .6

+ 3 .9 - 3 .2

; µ+µ-= 1 .9

+ 2 .2 - 1 .5

+ 14 + 6 - 12 - 7

nb / N
Roberto Spighi (HERA-B coll.) Recent results from HERA-B

QFTHEP, 17-23 June 2004

(28)


Open beauty production Open beauty production
Analysis · 35% of · Expect · Carbon of 2002/03 data: e+e- and µ+µ- statistics NB ~ 100 for full sample + Tungsten targets

· J/ acceptance: -0.35
· Preliminary results of both channels compatible · 1.5 lower than 2000 result

bb = 12.3
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.)

()

+ 3.5 - 3.2

nb / N
(29)

Recent results from HERA-B


Hidden beauty production Hidden beauty production
=
J /

n nJ

/

Br ( J / l + l - ) J +- Br ( l l )

/

pN + X, µ+µ-, e+e-

Drell-Yan

Drell-Yan

Comb. BG

Comb. BG

Drell-Yan contribution compatible with E866

M(µ+µ-) (GeV/c2)

M(e+e-) (GeV/c2)

Relative production of (1S)/(2S)/(3S) fixed on E605 data
Roberto Spighi (HERA-B coll.) Recent results from HERA-B

QFTHEP, 17-23 June 2004

(30)


Hidden beauty production Hidden beauty production
Events µ+µ e+e
-

Br· d/dy

y=0

33±7 31±10

3.9±1.1 pb/N 2.9±1.2 pb/N 3.4±0.8 pb/N

-

both

·

All C and W data used (150 M evts)

Not used in fit

· Modified Craigie applied to allow for nuclear suppression: =0.99±0.05

Br â

d dy

y =0

m ( s ) = o ex p - o A s

-1

s (GeV)
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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Hard photon analysis Hard photon analysis
Direct production: dominant process gq q Unique sensitivity to gluon density function
E( /d p ) , arbitrary units d

pC X,S=41.6 GeV, HERA-B preliminary
7 6 5 4 3 2

10 10 10 10 10 10 10

MinBias data, run 20478 HP trigger, run 20575 MB Monte Carlo

3

Main bkg sources, also important to test QCD

pC°X

3

HERA-B: 1 · Widest rapidity range 10 · Large pT range 10 · Highest energy for pA pCX 10 · Ongoing analysis on 10 0 1 2 3 4 5 6 7 8 heavier materials E , GeV (normalization still arbitrary)
-1 -2 -3 -4
T

pCX
Recent results from HERA-B

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

(32)


MB data analysis MB data analysis

-

-

- Pentaquark search - Pentaquark search

Hyperon production Hyperon production Strangeness production Strangeness production

Open charm production Open charm production V0 production V0 production

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

(33)


Open charm production Open charm production
Signals selected in Minimum Bias data D0 K- + + c.c. D+ K- + + + c.c.
D*+ D0+

+ c.c.

K- + +

N = 189 ± 20 = 25 ± 3 MeV M = 1863 ± 3 MeV

N = 98 ± 12 = 15 ± 2 MeV M = 1866 ± 2 MeV

N = 43 ± 8 = 0.89 ± 0.15 MeV q = 145.9 ± 0.2 MeV

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

(34)


Open charm production Open charm production
preliminary (D0)µb/Nucl (D+)µb/Nucl R(D+/D0)
µb/Nucl

-0.1 < xF < 0.05 21.4±3.2±3.6 11.5±1.7±2.2

full xF 56.3±8.5±9.5 30.2±4.5±5.8 0.54±0.11±0.14

Important test for QCD

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

(35)


V00 V
KS+
-

production production
p-beam

V
0

p A

p

-

Armenteros-Podolanski plot

Statistics:
Ks ~ 3.40 x 106 evts ~ 4.9 MeV ~ 0.94 x 106 " ~ 1.8 MeV ~ 0.45 x 106 " ~ 1.8 MeV

Measurement of the production cross section and ratio vs A 2000 data analysis published in: Eur.Phys.J. C 29,181 (2003)
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

(36)


Hyperon production Hyperon production
(1520) p K- + c.c.
(Carbon target)

± (1321) (1116)
x103 6

±

(all targets)

4

2

0 1.2

1.3 1.4 Mass GeV/c2

1.5

Strong signals

: ~ 2000, ~ 8 MeV : ~ 1000, ~ 8 MeV -: ~ 11300, ~ 2.6 MeV +: ~ 7700, ~ 2.6 MeV

· Good proton/kaon identification · Very large ± statistics
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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Pentaquark search Pentaquark search
Possible pentaquark states +(1530, uudds) pK0 (or nK+) - - (ddssu) - - (or - K-) --
and charge c.

wire K-(us) or (uds) p + (uudds) K0 p

Use the full MB data sample (~210M evts, 3 nuclear targets C, Ti, W) to: · search for the reported pentaquark signals · provide upper limits on particle yield ratios (vs (1520) and 0(1530)) · possibly determine physical quantities (width, spin, parity, charge) of pentaquarks for different final states (p-K0, -)
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

(38)


Pentaquark search: ++ pK00 Pentaquark search: pK

sensitivity in BR·(d/dxf) ~ 5µb/nucleon

· No evidence of signals where expected (~ 1530 MeV/c2) · Upper limit on particle yield ratio: +/1520 < 0.02 at 95% C.L. assuming BR(+ pKS) = 0.25 (Hermes: ~ 1.6 Â 3.5) · Upper limit on nuclear cross section under evaluation
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

(39)


Pentaquark search: ----(++) ----((+++)) (++) + Pentaquark search:
- + + + -

0(1530)

Good 0(1530) reconstruction
· No evidence of - -, 1862 MeV/c2
++

around

- - + + +

- -, ++

· Upper limits (95% cl): --(1862) / 0(1530) < 0.077 ++(1862) / 0(1530) < 0.058 · Nuclear cross section upper limit in progress

QFTHEP, 17-23 June 2004

Roberto Spighi (HERA-B coll.)

Recent results from HERA-B

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Summary Summary
Many physics topics addressed Detector Large statistics collected
MB sample Large acceptance (negative xF) good particle identification Dilepton sample (µ+µ- & e+e-)

J/ (300k), (2S), c, and bb Open charm, V0, hyperons, pentaquark

High quality of data Preliminary results available on several topics Competitive with previous experimental panorama
Many thanks to the organizers for the invitation and the logistic support
QFTHEP, 17-23 June 2004 Roberto Spighi (HERA-B coll.) Recent results from HERA-B

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