1 on the total charm production cross section in hadronic interactions at high energies √s > 1...
DESCRIPTION
3 1. Single diffractive dissociation Data on σ tot ( pp cc + X ) at s = 20 − 40 GeV Data on σ tot ( pp cc + X ) at s = 20 − 40 GeV The assumption about the dominating contribution of The assumption about the dominating contribution of single dissociation processes into the total cross section of charm production at low energies. single dissociation processes into the total cross section of charm production at low energies. Additive quark model and quark statistics rules Additive quark model and quark statistics rules The additional set of experimental data: The additional set of experimental data: SPS, TEVATRON data on σ DD (pp X) SPS, TEVATRON data on σ DD (pp X) at s = 200, 546, 900 and 1800 GeV at s = 200, 546, 900 and 1800 GeVTRANSCRIPT
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On the total charm On the total charm production cross section in production cross section in
hadronichadronicinteractions at high interactions at high
energies energies √s > 1 TeV √s > 1 TeVYu.F. NovoseltsevYu.F. Novoseltsev, , G.M. VereshkovG.M. Vereshkov
Institute for Nuclear Researsh of RAS,Physics Research Institute of Rostov State University
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We assume that the charmed We assume that the charmed particles are produced inparticles are produced in
single single diffractive dissociationdiffractive dissociation double double diffractive dissociatiodiffractive dissociationn hard parton-parton collisions (phard parton-parton collisions (pt t > 1 GeV)> 1 GeV)
We estimate cross sections of these We estimate cross sections of these processesprocesses
on the base of experimental dataon the base of experimental data
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1. Single 1. Single diffractive diffractive dissociationdissociation
Data on Data on σσtottot( pp ( pp cc + X cc + X)) at at s = 20 − 40 GeV s = 20 − 40 GeV The assumption about the dominating contributionThe assumption about the dominating contribution
of of single single dissociationdissociation processes into the total cross processes into the total cross
section of charm production at low energies.section of charm production at low energies. Additive Additive quark model and quark model and quark statistics rulesquark statistics rules The additional set of experimental data:The additional set of experimental data: SPS, SPS, TEVATRON data on TEVATRON data on σσDDDD(pp (pp X) X) at at s = 200, 546, 900 and 1800 GeVs = 200, 546, 900 and 1800 GeV
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Data on total cross section of charm Data on total cross section of charm production production
at at s = 20 − 40 GeVs = 20 − 40 GeVFirst of all, we clear up the opportunities of AQM and
logarithmic dependence for cross section in the description of data on charm production in pN and N interactions at low
energies:
σpNcc+X (s) = CpN ln(s/so)
σNcc+X(s) = ⅔ σpNcc+X(3s/2)
CpN = 28.84 ± 2.10 μb, √so = 18.51 ± 0.36 GeV , 2 = 0.89 (1)
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The fit result enables us to make an assumption The fit result enables us to make an assumption about about
the dominating contribution of diffractive the dominating contribution of diffractive processes into processes into
the total cross section of charm production at low the total cross section of charm production at low energiesenergies
in the region of low energies the probability of double in the region of low energies the probability of double dissociation processes is low,dissociation processes is low, the contribution of hard processes is small, because the contribution of hard processes is small, because partons with small values of Bjorken's variable x (those partons with small values of Bjorken's variable x (those are many) do not participate in the c-quark production.are many) do not participate in the c-quark production.
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At high energies we use an additional set of experimental data. At high energies we use an additional set of experimental data. The estimation of difractive production cross section is based on The estimation of difractive production cross section is based on
processing of collider data on diffractive dissociation with use of processing of collider data on diffractive dissociation with use of quark statistics rules.quark statistics rules.
Cross section of diffractive dissociation in pp-interactons:Cross section of diffractive dissociation in pp-interactons: SPS --- SPS --- √s = 200 GeV, 900 GeV (Ansorge et al., 1986)√s = 200 GeV, 900 GeV (Ansorge et al., 1986) TEVATRON --- √s = 546 GeV, 1800 Gev (Abe et al., 1994)TEVATRON --- √s = 546 GeV, 1800 Gev (Abe et al., 1994)
σσDDDD(pp (pp X) = C X) = CDDDD ln(s/s ln(s/soo))
charm production cross section is extracted fromcharm production cross section is extracted from total cross section by quark statistics rules:total cross section by quark statistics rules:
σσ( pp ( pp cc + X) ≈ k cc + X) ≈ kcccc× × σσDDDD(pp (pp X), k X), kcccc ≈ 0.025 ± 0.004 ≈ 0.025 ± 0.004 uu : dd : ss : cc = 1 : 1 : (0.38 ± 0.07) : (0.06 ± 0.01)uu : dd : ss : cc = 1 : 1 : (0.38 ± 0.07) : (0.06 ± 0.01)
λλqq = ∑ = ∑
2Ji +1
Mi2
i
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σσ(pp (pp cc +X) at collider energies cc +X) at collider energies √√s, GeV 200 546 900 1800s, GeV 200 546 900 1800
σσDDDD, mb 4.8 ± 0.5 7.89 ± 0.33 7.8 ± 0.5 9.46 ± , mb 4.8 ± 0.5 7.89 ± 0.33 7.8 ± 0.5 9.46 ± 0.440.44
σσ(pp (pp cc +X) cc +X) = k= kcccc × × σσDD DD ,, (2)(2) σσpp pp cc +X cc +X, , μμb 120 ± 21 197 ± 32 195 ± 32 236 ± 38b 120 ± 21 197 ± 32 195 ± 32 236 ± 38
The obtained values of charm production cross section have the statusof model dependent processing collider data
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Joint fit ofJoint fit of low-energylow-energy and high-energy data and high-energy data on difractive charm productionon difractive charm production
σσ(pp (pp cc +X) = C*ln(s/s cc +X) = C*ln(s/soo))C = 26.78 ± 1.44 μb√so = 18.23 ± 0.23 GeVχ2/dof = 0.98
(3)
Values of C and sValues of C and soo in in (1) and (3) coincide (1) and (3) coincide within the limits of within the limits of statistical errorsstatistical errors
The strip correspondsThe strip correspondsto 90 % CLto 90 % CL
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2. 2. Double diffractive Double diffractive dissociationdissociation
√√s, GeV s, GeV 200 200 900 900σσ2DD2DD, mb , mb 3.53.5 ± ± 2.22.2 4.0 4.0 ±± 2.5 2.5
Ansorge et al (CERN-UA-005 Collaboration), 1986
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σσ2DD2DD(s)(s)
σσDDDD(s)(s)const + O(1/sn), n > 0, s ∞
1. σσ2DD2DD(s)(s) can not rise faster than ln s
2.
σσ2DD2DD(pp X) = C(pp X) = C2DD 2DD ln s/sln s/so o , C, C2DD 2DD = 584 = 584 ± 263 ± 263 μμb b
If
then
Using the quark statistics rules gives
σ(pp cc+X) = Cpp cc ln s/so
Cpp cc = 14.6 ± 7.0 μb, √so = 18.23 ± 0.33 GeV
(2DD)(2DD)
(2DD)
(4)
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3. Hard processes3. Hard processes
These data are fit very well (χ2/dof=0.092) by power functions
dσdt
ADx
(t/μ2 + 1)n, t = ( p )2=
The parameters μ = 2.451 ± 0.143 GeV and n = 3.275 ± 0.031
are the same to all channels
p ≥ μhard = ?
┴
┴
D. Acosta et al , 2003 √s = 1.96 TeV
dσ/d
t, nb
/GeV
2
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tto o = = μμhard hard ≈ m≈ mcc22
(5)
(6)
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1313
A = 0.921 ± 0.106, 1/μ2 = 1.346 ± 0.115 mb,K = 0.081 ± 0.005,Λ = 5.161 ± 1.361 GeV
χ2/dof = 0.275
(7)
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The upper bound of the cross section σσ pp pp cc + X cc + X is obtained with the assumption
(8)
hard
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(9)
σpNcc+X (s) = σDD(s) + σ2DD (s) + σhard (s)tot
μhard = 1.2 GeV
The upper bound of the total charm production cross section
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“1” – present workσpNcc+X = 1210 ± 400 μb at √s = 1.96 TeV,
σpNcc+X = 1590 ± 540 μb at √s = 14 TeV,
2 -- R.Vogt. NLO pQCD (2003)3 – L.Volkova, G.Zatsepin (2001)
μhard = 1.0 GeV
μhard = 1.5 GeV
μb