HERAFitter Alekhin, S.; Behnke, O.; Belov, P. ...
The European physical journal. C, Particles and fields,
07/2015, Volume:
75, Issue:
7
Journal Article
Peer reviewed
Open access
HERAFitter is an open-source package that provides a framework for the determination of the parton distribution functions (PDFs) of the proton and for many different kinds of analyses in Quantum ...Chromodynamics (QCD). It encodes results from a wide range of experimental measurements in lepton–proton deep inelastic scattering and proton–proton (proton–antiproton) collisions at hadron colliders. These are complemented with a variety of theoretical options for calculating PDF-dependent cross section predictions corresponding to the measurements. The framework covers a large number of the existing methods and schemes used for PDF determination. The data and theoretical predictions are brought together through numerous methodological options for carrying out PDF fits and plotting tools to help to visualise the results. While primarily based on the approach of collinear factorisation, HERAFitter also provides facilities for fits of dipole models and transverse-momentum dependent PDFs. The package can be used to study the impact of new precise measurements from hadron colliders. This paper describes the general structure of HERAFitter and its wide choice of options.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the present paper, the ATLAS inclusive W± and Z boson production data are analyzed together with the CMS inclusive W± and Z boson production data to investigate any possible tensions between the ...data sets and to determine the strange sea fraction, within the framework of a parton distribution function fit at next-to next-to-leading order in perturbative QCD.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
A phenomenological study of the final combined HERA data on inclusive deep inelastic scattering has been performed. The data are presented and investigated for a kinematic range extending from values ...of the four-momentum transfer, Q2, above 104 GeV2 down to the lowest values observable at HERA of Q2=0.045 GeV2 and Bjorken x, xBj=6×10−7. The data are well described by fits based on perturbative quantum chromodynamics (QCD) using collinear factorisation and evolution of the parton densities encompassed in the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi formalism from the highest Q2 down to Q2 of a few GeV2. The Regge formalism with the soft Pomeron pole can describe the data up to Q2≈0.65 GeV2. The complete data set can be described by a new fit using the Abramowicz-Levin-Levy-Maor parametrization. The region between the Regge and the perturbative QCD regimes is of particular interest.
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Background
Previous studies have indicated that in patients with atopic dermatitis (AD) and birch pollen allergy pollen‐related foods are able to cause late eczematous response. However, the ...relevance of AD worsening by ingestion of birch pollen‐related foods is still a matter of debate.
Objective
The purpose of this retrospective study was to determine how frequently birch pollen‐related foods induce a deterioration of eczema. Additionally, the diagnostic value of specific IgE (sIgE) determination was evaluated.
Methods
A total of 182 children and adults with AD and suspected birch pollen‐related food allergy underwent 261 double‐blind placebo‐controlled food challenges (DBPCFC). Total and sIgE levels were determined prior to DBPCFC.
Results
Sixty‐five patients developed allergic reactions (responders) upon DBPCFC with birch pollen‐related foods (n = 103 DBPCFC). Of these, 32 patients exhibited significant deterioration of AD defined as a median increase of 15.4 severity scoring of atopic dermatitis index points (95% CI 12.4‐16.3) from baseline making up 37% of all positive reactions. Responders showed significantly higher sIgE levels to birch pollen and apple as well as a higher prevalence of allergic rhinoconjunctivitis compared to nonresponders (P < .05). However, patients with late eczematous response could not be differentiated from those with isolated immediate‐type reactions by sIgE levels.
Conclusion
In a subpopulation of patients with AD and birch pollen sensitization, related foods should be considered as a trigger for an aggravation of eczema. As sufficient markers for prediction of late eczematous reactions are still lacking, DBPCFC cannot be replaced in diagnosis of birch pollen‐related foods in patients with AD.
Clinical implications
In patients with AD and birch pollen allergy, birch pollen‐related foods should be considered as a provocation factor for an aggravation of disease signs and symptoms.
Thirty‐seven percent of all positive reactions to birch pollen‐related foods were associated with a significant deterioration of atopic dermatitis (AD). Responders showed significantly higher sIgE levels to birch pollen and apple as well as a higher prevalence of allergic rhinoconjunctivitis compared to nonresponders (P < .05). In patients with AD and birch pollen allergy, birch pollen‐related foods should be considered as a provocation factor for an aggravation of dermatitis even in the absence of immediate‐type reaction to birch pollen‐related foods.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Azimuthal correlations in
Z
+
jet production at large transverse momenta are computed by matching Parton-Branching (PB) TMD parton distributions and showers with NLO calculations via MCatNLO. The ...predictions are compared with those for dijet production in the same kinematic range. The azimuthal correlations
Δ
ϕ
between the Z boson and the leading jet are steeper compared to those in dijet production at transverse momenta
O
(
100
)
GeV , while they become similar for very high transverse momenta
O
(
1000
)
GeV . The different patterns of
Z
+
jet and dijet azimuthal correlations can be used to search for potential
factorization-breaking
effects in the back-to-back region, which depend on the different color and spin structure of the final states and their interferences with the initial states. In order to investigate these effects experimentally, we propose to measure the ratio of the distributions in
Δ
ϕ
for
Z
+
jet- and multijet production at low and at high transverse momenta, and compare the results to predictions obtained assuming factorization. We examine the role of theoretical uncertainties by performing variations of the factorization scale, renormalization scale and matching scale. In particular, we present a comparative study of matching scale uncertainties in the cases of PB-TMD and collinear parton showers.
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6.
The Platformization of Brands Wichmann, Julian R.K.; Wiegand, Nico; Reinartz, Werner J.
Journal of marketing,
01/2022, Volume:
86, Issue:
1
Journal Article
Peer reviewed
Open access
Digital platforms that aggregate products and services, such as Google Shopping or Amazon, have emerged as powerful intermediaries to brand offerings, challenging traditional product brands that have ...largely lost direct access to consumers. As a countermeasure, several long-established brands have built their own flagship platforms to resume control and foster consumer loyalty. For example, sports brands such as Nike, Adidas, or Asics launched tracking and training platforms that allow for ongoing versatile interactions among participants beyond product purchase. The authors analyze these emerging platform offerings, whose potential brands struggle to exploit, and provide guidance for brands that aim to platformize their business. This guidance comprises the conceptualization of digital platforms as places of consumer crowdsourcing (i.e., consumers drawing value from platform participants such as the brand, other consumers, or third-party businesses) and crowdsending (i.e., consumers providing value to platform participants) of products, services, and content along with a well-defined framework that brands can apply to assemble different types of flagship platforms. Evaluating the consequences of crowdsourcing and crowdsending for consumer–platform relationships, the authors derive a typology of archetypical relationship states and develop a set of propositions to help offline-born product brands thrive through platformization.
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IZUM, KILJ, NUK, OILJ, PILJ, SAZU, UKNU, UL, UM, UPUK
Abstract
Azimuthal correlations in
$$\mathrm {Z} +$$
Z
+
jet production at large transverse momenta are computed by matching Parton-Branching (PB) TMD parton distributions and showers with NLO ...calculations via MCatNLO. The predictions are compared with those for dijet production in the same kinematic range. The azimuthal correlations
$$\Delta \phi $$
Δ
ϕ
between the Z boson and the leading jet are steeper compared to those in dijet production at transverse momenta
$$\mathcal{O}(100)$$
O
(
100
)
GeV , while they become similar for very high transverse momenta
$${{\mathcal {O}}}(1000)$$
O
(
1000
)
GeV . The different patterns of
$$\mathrm {Z} +$$
Z
+
jet and dijet azimuthal correlations can be used to search for potential
factorization-breaking
effects in the back-to-back region, which depend on the different color and spin structure of the final states and their interferences with the initial states. In order to investigate these effects experimentally, we propose to measure the ratio of the distributions in
$$\Delta \phi $$
Δ
ϕ
for
$$\mathrm {Z} +$$
Z
+
jet- and multijet production at low and at high transverse momenta, and compare the results to predictions obtained assuming factorization. We examine the role of theoretical uncertainties by performing variations of the factorization scale, renormalization scale and matching scale. In particular, we present a comparative study of matching scale uncertainties in the cases of PB-TMD and collinear parton showers.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A
bstract
Two-particle azimuthal correlations have been measured in neutral current deep inelastic
ep
scattering with virtuality
Q
2
>
5 GeV
2
at a centre-of-mass energy
s
= 318 GeV recorded with the ...ZEUS detector at HERA. The correlations of charged particles have been measured in the range of laboratory pseudorapidity
−
1
.
5
< η <
2
.
0 and transverse momentum 0
.
1
< p
T
<
5
.
0 GeV and event multiplicities
N
ch
up to six times larger than the average 〈
N
ch
〉 ≈ 5. The two-particle correlations have been measured in terms of the angular observables
c
n
{2}
= 〈〈
cosn
Δ
φ
〉〉, where
n
is between 1 and 4 and ∆
φ
is the relative azimuthal angle between the two particles. Comparisons with available models of deep inelastic scattering, which are tuned to reproduce inclusive particle production, suggest that the measured two-particle correlations are dominated by contributions from multijet production. The correlations observed here do not indicate the kind of collective behaviour recently observed at the highest RHIC and LHC energies in high-multiplicity hadronic collisions.
A new measurement of inclusive-jet cross sections in the Breit frame in neutral current deep inelastic scattering using the ZEUS detector at the HERA collider is presented. The data were taken in the ...years 2004–2007 at a centre-of-mass energy of
318
GeV
and correspond to an integrated luminosity of
347
pb
-
1
. The jets were reconstructed using the
k
t
-algorithm in the Breit reference frame. They have been measured as a function of the squared momentum transfer,
Q
2
, and the transverse momentum of the jets in the Breit frame,
p
⊥
,
Breit
. The measured jet cross sections are compared to previous measurements and to perturbative QCD predictions. The measurement has been used in a next-to-next-to-leading-order QCD analysis to perform a simultaneous determination of parton distribution functions of the proton and the strong coupling, resulting in a value of
α
s
(
M
Z
2
)
=
0.1142
±
0.0017
(experimental/fit)
-
0.0007
+
0.0006
(model/parameterisation)
-
0.0004
+
0.0006
(scale)
, whose accuracy is improved compared to similar measurements. In addition, the running of the strong coupling is demonstrated using data obtained at different scales.
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A
bstract
Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-multiplicity
ep
scattering at a centre-of-mass energy
s
= 318 GeV with the ZEUS detector at ...HERA. Two- and four-particle azimuthal correlations, as well as multiplicity, transverse momentum, and pseudorapidity distributions for charged-particle multiplicities
N
ch
≥ 20 are measured. The dependence of two-particle correlations on the virtuality of the exchanged photon shows a clear transition from photoproduction to neutral current deep inelastic scattering. For the multiplicities studied, neither the measurements in photoproduction processes nor those in neutral current deep inelastic scattering indicate significant collective behaviour of the kind observed in high-multiplicity hadronic collisions at RHIC and the LHC. Comparisons of PYTHIA predictions with the measurements in photoproduction strongly indicate the presence of multiparton interactions from hadronic fluctuations of the exchanged photon.
PDF
