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Study of hard double-parton scattering in four-jet events in pp collisions at $\sqrt{s}=7$ TeV with the ATLAS experiment

The collaboration
JHEP 1611 (2016) 110, 2016

Abstract (data abstract)
Inclusive four-jet events produced in proton--proton collisions at a centre-of-mass energy of sqrt{s} = 7 TeV are analysed for the presence of hard double-parton scattering using data corresponding to an integrated luminosity of 37.3 pb^-1, collected with the ATLAS detector at the LHC. The contribution of hard double-parton scattering to the production of four-jet events is extracted using an artificial neural network, assuming that hard double-parton scattering can be approximated by an uncorrelated overlaying of dijet events. For events containing at least four jets with transverse momentum p_T > 20 GeV and pseudorapidity eta < 4.4, and at least one having p_T > 42.5 GeV, the contribution of hard double-parton scattering is estimated to be f_{DPS} = 0.092 ^{+0.005}_{-0.011} (stat.) ^{+0.033}_{-0.037} (syst.). After combining this measurement with those of the inclusive dijet and four-jet cross-sections in the appropriate phase space regions, the effective cross-section, sigma_{eff}, was determined to be sigma_{eff} = 14.9 ^{+1.2}_{-1.0} (stat.) ^{+5.1}_{-3.8} (syst.) mb. This result is consistent within the quoted uncertainties with previous measurements of sigma_{eff}, performed at centre-of-mass energies between 63 GeV and 8 TeV using various final states, and it corresponds to 21^{+7}_{-6}% of the total inelastic cross-section measured at sqrt{s} = 7 TeV. The distributions of the observables sensitive to the contribution of hard double-parton scattering, corrected for detector effects, are also provided UPDATE 29/09/2016: The normalisation of all plots was changed to take into account the bin width correctly. As all distributions have a constant bin width, the change is a trivial overall scaling factor for all distributions.

• #### Table 1

Data from Figure 10(a)

10.17182/hepdata.73908.v1/t1

Normalized distribution of the variable $\Delta^{p_{\mathrm{T}}}_{34}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 2

Data from Figure 10(b)

10.17182/hepdata.73908.v1/t2

Normalized distribution of the variable $\Delta\phi_{34}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 3

Data from Figure 11(a)

10.17182/hepdata.73908.v1/t3

Normalized distribution of the variable $\Delta^{p_{\mathrm{T}}}_{12}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 4

Data from Figure 11(b)

10.17182/hepdata.73908.v1/t4

Normalized distribution of the variable $\Delta^{p_{\mathrm{T}}}_{13}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 5

Data from Figure 11(c)

10.17182/hepdata.73908.v1/t5

Normalized distribution of the variable $\Delta^{p_{\mathrm{T}}}_{23}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 6

Data from Figure 11(d)

10.17182/hepdata.73908.v1/t6

Normalized distribution of the variable $\Delta^{p_{\mathrm{T}}}_{14}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 7

Data from Figure 12(a)

10.17182/hepdata.73908.v1/t7

Normalized distribution of the variable $\Delta^{p_{\mathrm{T}}}_{24}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 8

Data from Figure 12(b)

10.17182/hepdata.73908.v1/t8

Normalized distribution of the variable $\Delta\phi_{12}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 9

Data from Figure 12(c)

10.17182/hepdata.73908.v1/t9

Normalized distribution of the variable $\Delta\phi_{13}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 10

Data from Figure 12(d)

10.17182/hepdata.73908.v1/t10

Normalized distribution of the variable $\Delta\phi_{23}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 11

Data from Figure 13(a)

10.17182/hepdata.73908.v1/t11

Normalized distribution of the variable $\Delta\phi_{14}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 12

Data from Figure 13(b)

10.17182/hepdata.73908.v1/t12

Normalized distribution of the variable $\Delta\phi_{24}$, defined in Eq (16) of the paper, in data after unfolding to particle level.

• #### Table 13

Data from Figure 13(c)

10.17182/hepdata.73908.v1/t13

Normalized distribution of the variable $\Delta y_{12}$, defined in Eq (16) of the paper, in data after unfolding to particle...

• #### Table 14

Data from Figure 13(d)

10.17182/hepdata.73908.v1/t14

Normalized distribution of the variable $\Delta y_{34}$, defined in Eq (16) of the paper, in data after unfolding to particle...

• #### Table 15

Data from Figure 14(a)

10.17182/hepdata.73908.v1/t15

Normalized distribution of the variable $\Delta y_{13}$, defined in Eq (16) of the paper, in data after unfolding to particle...

• #### Table 16

Data from Figure 14(b)

10.17182/hepdata.73908.v1/t16

Normalized distribution of the variable $\Delta y_{23}$, defined in Eq (16) of the paper, in data after unfolding to particle...

• #### Table 17

Data from Figure 14(c)

10.17182/hepdata.73908.v1/t17

Normalized distribution of the variable $\Delta y_{14}$, defined in Eq (16) of the paper, in data after unfolding to particle...

• #### Table 18

Data from Figure 14(d)

10.17182/hepdata.73908.v1/t18

Normalized distribution of the variable $\Delta y_{24}$, defined in Eq (16) of the paper, in data after unfolding to particle...

• #### Table 19

Data from Figure 15(a)

10.17182/hepdata.73908.v1/t19

Normalized distribution of the variable $\phi_{1+2} - \phi_{3+4}$, defined in Eq (16) of the paper, in data after unfolding to...

• #### Table 20

Data from Figure 15(b)

10.17182/hepdata.73908.v1/t20

Normalized distribution of the variable $\phi_{1+3} - \phi_{2+4}$, defined in Eq (16) of the paper, in data after unfolding to...

• #### Table 21

Data from Figure 15(c)

10.17182/hepdata.73908.v1/t21

Normalized distribution of the variable $\phi_{1+4} - \phi_{2+3}$, defined in Eq (16) of the paper, in data after unfolding to...