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The Large Hadron electron Collider as a bridge project for CERN
Authors:
F. Ahmadova,
K. André,
N. Armesto,
G. Azuelos,
O. Behnke,
M. Boonekamp,
M. Bonvini,
D. Britzger,
O. Brüning,
T. A. Bud,
A. M. Cooper-Sarkar,
J. D'Hondt,
M. D'Onofrio,
O. Fischer,
L. Forthomme,
F. Giuli,
C. Gwenlan,
E. Hammou,
B. Holzer,
H. Khanpour,
U. Klein,
P. Kostka,
T. Lappi,
H. Mäntysaari,
B. Mellado
, et al. (17 additional authors not shown)
Abstract:
The LHeC is the project for delivering electron-nucleon collisions at CERN using the HL-LHC beams. An Energy Recovery Linac in racetrack configuration will provide 50 GeV electrons to achieve centre-of-mass energies around 1 TeV/nucleon and instantaneous luminosities around $10^{34}$ cm$^{-2}$s$^{-1}$. The LHeC program elaborated in the CDR of 2021 included a phase with concurrent operation of ele…
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The LHeC is the project for delivering electron-nucleon collisions at CERN using the HL-LHC beams. An Energy Recovery Linac in racetrack configuration will provide 50 GeV electrons to achieve centre-of-mass energies around 1 TeV/nucleon and instantaneous luminosities around $10^{34}$ cm$^{-2}$s$^{-1}$. The LHeC program elaborated in the CDR of 2021 included a phase with concurrent operation of electron-hadron and hadron-hadron collisions, followed by a standalone phase of electron-hadron collisions only. In view of the current HL-LHC schedule, in this paper we have examined the possibilities of a program after the regular HL-LHC program with only electron-proton operation. In this operation mode, the LHeC would serve as an impactful bridge project between major colliders at CERN. The standalone physics program comprises electroweak, Higgs, top-quark, BSM and strong-interaction physics. In addition, it empowers the physics analyses at the HL-LHC by retrofitting measurements and searches with significantly more precise knowledge of the proton structure and $α_s$. The accelerator technology deployed in the Energy Recovery Linac for the LHeC is a major stepping-stone for the performance, cost reduction and training for future colliders. The capital investments in the LHeC electron accelerator can be reused in a cost-efficient way as the injector for the FCC-ee. Finally, data from the LHeC are essential to enable the physics potential of any new high-energy hadron collider. The operational plan of 6 years easily fits in the period between two major colliders at CERN. Similar to the LHeC empowering the HL-LHC physics program, the FCC-eh would be an impactful addition to the FCC physics program.
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Submitted 24 October, 2025; v1 submitted 22 March, 2025;
originally announced March 2025.
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Robust semi-parametric signal detection in particle physics with classifiers decorrelated via optimal transport
Authors:
Purvasha Chakravarti,
Lucas Kania,
Olaf Behnke,
Mikael Kuusela,
Larry Wasserman
Abstract:
Searches for signals of new physics in particle physics are usually done by training a supervised classifier to separate a signal model from the known Standard Model physics (also called the background model). However, even when the signal model is correct, systematic errors in the background model can influence supervised classifiers and might adversely affect the signal detection procedure. To t…
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Searches for signals of new physics in particle physics are usually done by training a supervised classifier to separate a signal model from the known Standard Model physics (also called the background model). However, even when the signal model is correct, systematic errors in the background model can influence supervised classifiers and might adversely affect the signal detection procedure. To tackle this problem, one approach is to use the (possibly misspecified) classifier only to perform a preliminary signal-enrichment step and then to carry out a signal detection test on the signal-rich sample. For this procedure to work, we need a classifier constrained to be decorrelated with one or more protected variables used for the signal-detection step. We do this by considering an optimal transport map of the classifier output that makes it independent of the protected variable(s) for the background. We then fit a semiparametric mixture model to the distribution of the protected variable after making cuts on the transformed classifier to detect the presence of a signal. We compare and contrast this decorrelation method with previous approaches, show that the decorrelation procedure is robust to moderate background misspecification, and analyze the power and validity of the signal detection test as a function of the cut on the classifier both with and without decorrelation. We conclude that decorrelation and signal enrichment help produce a stable, robust, valid, and more powerful test.
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Submitted 3 November, 2025; v1 submitted 10 September, 2024;
originally announced September 2024.
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Search for effective Lorentz and CPT violation using ZEUS data
Authors:
ZEUS collaboration,
I. Abt,
R. Aggarwal,
V. Aushev,
O. Behnke,
A. Bertolin,
I. Bloch,
I. Brock,
N. H. Brook,
R. Brugnera,
A. Bruni,
P. J. Bussey,
A. Caldwell,
C. D. Catterall,
J. Chwastowski,
J. Ciborowski,
R. Ciesielski,
A. M. Cooper-Sarkar,
M. Corradi,
R. K. Dementiev,
S. Dusini,
J. Ferrando,
B. Foster,
E. Gallo,
D. Gangadharan
, et al. (55 additional authors not shown)
Abstract:
Lorentz and CPT symmetry in the quark sector of the Standard Model are studied in the context of an effective field theory using ZEUS $e^{\pm} p$ data. Symmetry-violating effects can lead to time-dependent oscillations of otherwise time-independent observables, including scattering cross sections. An analysis using five years of inclusive neutral-current deep inelastic scattering events correspond…
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Lorentz and CPT symmetry in the quark sector of the Standard Model are studied in the context of an effective field theory using ZEUS $e^{\pm} p$ data. Symmetry-violating effects can lead to time-dependent oscillations of otherwise time-independent observables, including scattering cross sections. An analysis using five years of inclusive neutral-current deep inelastic scattering events corresponding to an integrated HERA luminosity of $372\; \text{pb}^{-1}$ at $\sqrt{s} = 318$ Gev has been performed. No evidence for oscillations in sidereal time has been observed within statistical and systematic uncertainties. Constraints, most for the first time, are placed on 42 coefficients parameterising dominant CPT-even dimension-four and CPT-odd dimension-five spin-independent modifications to the propagation and interaction of light quarks.
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Submitted 24 December, 2022;
originally announced December 2022.
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Measurement of the cross-section ratio $σ_{ψ(2S )}/σ_{J/ψ(1S )}$ in exclusive photoproduction at HERA
Authors:
ZEUS Collaboration,
I. Abt,
M. Adamus,
R. Aggarwal,
V. Aushev,
O. Behnke,
A. Bertolin,
I. Bloch,
I. Brock,
N. H. Brook,
R. Brugnera,
A. Bruni,
P. J. Bussey,
A. Caldwell,
C. D. Catterall,
J. Chwastowski,
J. Ciborowski,
R. Ciesielski,
A. M. Cooper-Sarkar,
M. Corradi,
R. K. Dementiev,
S. Dusini,
J. Ferrando,
B. Foster,
E. Gallo
, et al. (58 additional authors not shown)
Abstract:
The exclusive photoproduction reactions $γp \to J/ψ(1S) p$ and $γp \to ψ(2S) p$ have been measured at an $ep$ centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 373 pb$^{-1}$. The measurement was made in the kinematic range $30 < W < 180$ GeV, $Q^2 < 1$ GeV$^2$ and $|t| < 1$ GeV$^2$, where $W$ is the photon--proton centre-of-mass energy, $Q^2$ is the…
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The exclusive photoproduction reactions $γp \to J/ψ(1S) p$ and $γp \to ψ(2S) p$ have been measured at an $ep$ centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 373 pb$^{-1}$. The measurement was made in the kinematic range $30 < W < 180$ GeV, $Q^2 < 1$ GeV$^2$ and $|t| < 1$ GeV$^2$, where $W$ is the photon--proton centre-of-mass energy, $Q^2$ is the photon virtuality and $t$ is the squared four-momentum transfer at the proton vertex. The decay channels used were $J/ψ(1S) \to μ^+ μ^-$, $ψ(2S) \to μ^+ μ^-$ and $ψ(2S) \to J/ψ(1S) π^+ π^-$ with subsequent decay $J/ψ(1S) \to μ^+ μ^-$. The ratio of the production cross sections, $R = σ_{ψ(2S)} / σ_{J/ψ(1S)}$, has been measured as a function of $W$ and $|t|$ and compared to previous data in photoproduction and deep inelastic scattering and with predictions of QCD-inspired models of exclusive vector-meson production, which are in reasonable agreement with the data.
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Submitted 27 December, 2022; v1 submitted 27 June, 2022;
originally announced June 2022.
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Impact of jet-production data on the next-to-next-to-leading-order determination of HERAPDF2.0 parton distributions
Authors:
H1,
ZEUS Collaborations,
:,
I. Abt,
R. Aggarwal,
V. Andreev,
M. Arratia,
V. Aushev,
A. Baghdasaryan,
A. Baty,
K. Begzsuren,
O. Behnke,
A. Belousov,
A. Bertolin,
I. Bloch,
V. Boudry,
G. Brandt,
I. Brock,
N. H. Brook,
R. Brugnera,
A. Bruni,
A. Buniatyan,
P. J. Bussey,
L. Bystritskaya,
A. Caldwell
, et al. (212 additional authors not shown)
Abstract:
The HERAPDF2.0 ensemble of parton distribution functions (PDFs) was introduced in 2015. The final stage is presented, a next-to-next-to-leading-order (NNLO) analysis of the HERA data on inclusive deep inelastic $ep$ scattering together with jet data as published by the H1 and ZEUS collaborations. A perturbative QCD fit, simultaneously of $α_s(M_Z^2)$ and and the PDFs, was performed with the result…
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The HERAPDF2.0 ensemble of parton distribution functions (PDFs) was introduced in 2015. The final stage is presented, a next-to-next-to-leading-order (NNLO) analysis of the HERA data on inclusive deep inelastic $ep$ scattering together with jet data as published by the H1 and ZEUS collaborations. A perturbative QCD fit, simultaneously of $α_s(M_Z^2)$ and and the PDFs, was performed with the result $α_s(M_Z^2) = 0.1156 \pm 0.0011~{\rm (exp)}~ ^{+0.0001}_{-0.0002}~ {\rm (model}$ ${\rm +~parameterisation)}~ \pm 0.0029~{\rm (scale)}$. The PDF sets of HERAPDF2.0Jets NNLO were determined with separate fits using two fixed values of $α_s(M_Z^2)$, $α_s(M_Z^2)=0.1155$ and $0.118$, since the latter value was already chosen for the published HERAPDF2.0 NNLO analysis based on HERA inclusive DIS data only. The different sets of PDFs are presented, evaluated and compared. The consistency of the PDFs determined with and without the jet data demonstrates the consistency of HERA inclusive and jet-production cross-section data. The inclusion of the jet data reduced the uncertainty on the gluon PDF. Predictions based on the PDFs of HERAPDF2.0Jets NNLO give an excellent description of the jet-production data used as input.
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Submitted 2 December, 2021;
originally announced December 2021.
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The Large Hadron-Electron Collider at the HL-LHC
Authors:
P. Agostini,
H. Aksakal,
S. Alekhin,
P. P. Allport,
N. Andari,
K. D. J. Andre,
D. Angal-Kalinin,
S. Antusch,
L. Aperio Bella,
L. Apolinario,
R. Apsimon,
A. Apyan,
G. Arduini,
V. Ari,
A. Armbruster,
N. Armesto,
B. Auchmann,
K. Aulenbacher,
G. Azuelos,
S. Backovic,
I. Bailey,
S. Bailey,
F. Balli,
S. Behera,
O. Behnke
, et al. (312 additional authors not shown)
Abstract:
The Large Hadron electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High Luminosity--Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent el…
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The Large Hadron electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High Luminosity--Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron-proton and proton-proton operation. This report represents an update of the Conceptual Design Report (CDR) of the LHeC, published in 2012. It comprises new results on parton structure of the proton and heavier nuclei, QCD dynamics, electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics in extending the accessible kinematic range in lepton-nucleus scattering by several orders of magnitude. Due to enhanced luminosity, large energy and the cleanliness of the hadronic final states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, the report represents a detailed updated design of the energy recovery electron linac (ERL) including new lattice, magnet, superconducting radio frequency technology and further components. Challenges of energy recovery are described and the lower energy, high current, 3-turn ERL facility, PERLE at Orsay, is presented which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution and calibration goals which arise from the Higgs and parton density function physics programmes. The paper also presents novel results on the Future Circular Collider in electron-hadron mode, FCC-eh, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies.
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Submitted 12 April, 2021; v1 submitted 28 July, 2020;
originally announced July 2020.
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Running of the Charm-Quark Mass from HERA Deep-Inelastic Scattering Data
Authors:
A. Gizhko,
A. Geiser,
S. Moch,
I. Abt,
O. Behnke,
A. Bertolin,
J. Blümlein,
D. Britzger,
R. Brugnera,
A. Buniatyan,
P. J. Bussey,
R. Carlin,
A. M. Cooper-Sarkar,
K. Daum,
S. Dusini,
E. Elsen,
L. Favart,
J. Feltesse,
B. Foster,
A. Garfagnini,
M. Garzelli,
J. Gayler,
D. Haidt,
J. Hladky,
A. W. Jung
, et al. (25 additional authors not shown)
Abstract:
Combined HERA data on charm production in deep-inelastic scattering have previously been used to determine the charm-quark running mass $m_c(m_c)$ in the MSbar renormalisation scheme. Here, the same data are used as a function of the photon virtuality $Q^2$ to evaluate the charm-quark running mass at different scales to one-loop order, in the context of a next-to-leading order QCD analysis. The sc…
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Combined HERA data on charm production in deep-inelastic scattering have previously been used to determine the charm-quark running mass $m_c(m_c)$ in the MSbar renormalisation scheme. Here, the same data are used as a function of the photon virtuality $Q^2$ to evaluate the charm-quark running mass at different scales to one-loop order, in the context of a next-to-leading order QCD analysis. The scale dependence of the mass is found to be consistent with QCD expectations.
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Submitted 24 May, 2017;
originally announced May 2017.
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Search for a narrow baryonic state decaying to ${pK^0_S}$ and ${\bar{p}K^0_S}$ in deep inelastic scattering at HERA
Authors:
ZEUS Collaboration,
H. Abramowicz,
I. Abt,
L. Adamczyk,
M. Adamus,
S. Antonelli,
V. Aushev,
O. Behnke,
U. Behrens,
A. Bertolin,
S. Bhadra,
I. Bloch,
E. G. Boos,
I. Brock,
N. H. Brook,
R. Brugnera,
A. Bruni,
P. J. Bussey,
A. Caldwell,
M. Capua,
C. D. Catterall,
J. Chwastowski,
J. Ciborowski,
R. Ciesielski,
A. M. Cooper-Sarkar
, et al. (102 additional authors not shown)
Abstract:
A search for a narrow baryonic state in the $pK^0_S$ and $\bar{p}K^0_S$ system has been performed in $ep$ collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb$^{-1}$ taken in 2003-2007. The search was performed with deep inelastic scattering events at an $ep$ centre-of-mass energy of 318 GeV for exchanged photon virtuality, $Q^2$, between 20 and 100 $\rm{} GeV^{2}$. C…
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A search for a narrow baryonic state in the $pK^0_S$ and $\bar{p}K^0_S$ system has been performed in $ep$ collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb$^{-1}$ taken in 2003-2007. The search was performed with deep inelastic scattering events at an $ep$ centre-of-mass energy of 318 GeV for exchanged photon virtuality, $Q^2$, between 20 and 100 $\rm{} GeV^{2}$. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb$^{-1}$ taken in 1996-2000, no resonance peak was found in the $p(\bar{p})K^0_S$ invariant-mass distribution in the range 1.45-1.7 GeV. Upper limits on the production cross section are set.
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Submitted 3 June, 2016; v1 submitted 7 April, 2016;
originally announced April 2016.
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Limits on the effective quark radius from inclusive $ep$ scattering at HERA
Authors:
ZEUS Collaboration,
H. Abramowicz,
I. Abt,
L. Adamczyk,
M. Adamus,
S. Antonelli,
V. Aushev,
O. Behnke,
U. Behrens,
A. Bertolin,
S. Bhadra,
I. Bloch,
E. G. Boos,
I. Brock,
N. H. Brook,
R. Brugnera,
A. Bruni,
P. J. Bussey,
A. Caldwell,
M. Capua,
C. D. Catterall,
J. Chwastowski,
J. Ciborowski,
R. Ciesielski,
A. M. Cooper-Sarkar
, et al. (103 additional authors not shown)
Abstract:
The high-precision HERA data allows searches up to TeV scales for Beyond the Standard Model contributions to electron-quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current $ep$ scattering corresponding to a luminosity of around 1 fb$^{-1}$ have been used in this analysis. A new approach to the beyond the Standard Model analysis of the…
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The high-precision HERA data allows searches up to TeV scales for Beyond the Standard Model contributions to electron-quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current $ep$ scattering corresponding to a luminosity of around 1 fb$^{-1}$ have been used in this analysis. A new approach to the beyond the Standard Model analysis of the inclusive $ep$ data is presented; simultaneous fits of parton distribution functions together with contributions of "new physics" processes were performed. Results are presented considering a finite radius of quarks within the quark form-factor model. The resulting 95% C.L. upper limit on the effective quark radius is $0.43\cdot 10^{-16}$ cm.
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Submitted 5 April, 2016;
originally announced April 2016.
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Combined QCD and electroweak analysis of HERA data
Authors:
ZEUS Collaboration,
H. Abramowicz,
I. Abt,
L. Adamczyk,
M. Adamus,
S. Antonelli,
V. Aushev,
O. Behnke,
U. Behrens,
A. Bertolin,
S. Bhadra,
I. Bloch,
E. G. Boos,
I. Brock,
N. H. Brook,
R. Brugnera,
A. Bruni,
P. J. Bussey,
A. Caldwell,
M. Capua,
C. D. Catterall,
J. Chwastowski,
J. Ciborowski,
R. Ciesielski,
A. M. Cooper-Sarkar
, et al. (102 additional authors not shown)
Abstract:
A simultaneous fit of parton distribution functions (PDFs) and electroweak parameters to HERA data on deep inelastic scattering is presented. The input data are the neutral current and charged current inclusive cross sections which were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In addition, the polarisation of the electron beam was taken into account for the ZEUS data rec…
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A simultaneous fit of parton distribution functions (PDFs) and electroweak parameters to HERA data on deep inelastic scattering is presented. The input data are the neutral current and charged current inclusive cross sections which were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In addition, the polarisation of the electron beam was taken into account for the ZEUS data recorded between 2004 and 2007. Results on the vector and axial-vector couplings of the Z boson to u- and d-type quarks, on the value of the electroweak mixing angle and the mass of the W boson are presented. The values obtained for the electroweak parameters are in agreement with Standard Model predictions.
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Submitted 13 May, 2016; v1 submitted 31 March, 2016;
originally announced March 2016.
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Summary of workshop on Future Physics with HERA Data
Authors:
A. Bacchetta,
J. Blümlein,
O. Behnke,
J. Dainton,
M. Diehl,
F. Hautmann,
A. Geiser,
H. Jung,
U. Karshon,
D. Kang,
P. Kroll,
C. Lee,
S. Levonian,
A. Levy,
E. Lohrmann,
S. Moch,
L. Motyka,
R. McNulty,
V. Myronenko,
E. R. Nocera,
S. Plätzer,
A. Rostomyan,
M. Ruspa,
M. Sauter,
G. Schnell
, et al. (8 additional authors not shown)
Abstract:
Recent highlights from the HERA experiments, Hermes, H1 and ZEUS, are reviewed and ideas for future analyses to fully exploit this unique data set are proposed. This document is a summary of a workshop on future physics with HERA data held at DESY, Hamburg at the end of 2014. All areas of HERA physics are covered and contributions from both experimentalists and theorists are included. The document…
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Recent highlights from the HERA experiments, Hermes, H1 and ZEUS, are reviewed and ideas for future analyses to fully exploit this unique data set are proposed. This document is a summary of a workshop on future physics with HERA data held at DESY, Hamburg at the end of 2014. All areas of HERA physics are covered and contributions from both experimentalists and theorists are included. The document outlines areas where HERA physics can still make a significant contribution, principally in a deeper understanding of QCD, and its relevance to other facilities. Within the framework of the Data Preservation in High Energy Physics, the HERA data have been preserved for analyses to take place over a timescale of 10 years and more. Therefore, although an extensive list of possibilities is presented here, safe storage of the data ensures that it can also be used in the far future should new ideas and analyses be proposed.
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Submitted 7 January, 2016;
originally announced January 2016.
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Charm, Beauty and Top at HERA
Authors:
O. Behnke,
A. Geiser,
M. Lisovyi
Abstract:
Results on open charm and beauty production and on the search for top production in high-energy electron-proton collisions at HERA are reviewed. This includes a discussion of relevant theoretical aspects, a summary of the available measurements and measurement techniques, and their impact on improved understanding of QCD and its parameters, such as parton density functions and charm- and beauty-qu…
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Results on open charm and beauty production and on the search for top production in high-energy electron-proton collisions at HERA are reviewed. This includes a discussion of relevant theoretical aspects, a summary of the available measurements and measurement techniques, and their impact on improved understanding of QCD and its parameters, such as parton density functions and charm- and beauty-quark masses. The impact of these results on measurements at the LHC and elsewhere is also addressed.
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Submitted 24 June, 2015;
originally announced June 2015.
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HERAFitter, Open Source QCD Fit Project
Authors:
S. Alekhin,
O. Behnke,
P. Belov,
S. Borroni,
M. Botje,
D. Britzger,
S. Camarda,
A. M. Cooper-Sarkar,
K. Daum,
C. Diaconu,
J. Feltesse,
A. Gizhko,
A. Glazov,
A. Guffanti,
M. Guzzi,
F. Hautmann,
A. Jung,
H. Jung,
V. Kolesnikov,
H. Kowalski,
O. Kuprash,
A. Kusina,
S. Levonian,
K. Lipka,
B. Lobodzinski
, et al. (28 additional authors not shown)
Abstract:
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. Thes…
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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 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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Submitted 29 May, 2015; v1 submitted 16 October, 2014;
originally announced October 2014.
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On the Relation of the LHeC and the LHC
Authors:
J. L. Abelleira Fernandez,
C. Adolphsen,
P. Adzic,
A. N. Akay,
H. Aksakal,
J. L. Albacete,
B. Allanach,
S. Alekhin,
P. Allport,
V. Andreev,
R. B. Appleby,
E. Arikan,
N. Armesto,
G. Azuelos,
M. Bai,
D. Barber,
J. Bartels,
O. Behnke,
J. Behr,
A. S. Belyaev,
I. Ben-Zvi,
N. Bernard,
S. Bertolucci,
S. Bettoni,
S. Biswal
, et al. (184 additional authors not shown)
Abstract:
The present note relies on the recently published conceptual design report of the LHeC and extends the first contribution to the European strategy debate in emphasising the role of the LHeC to complement and complete the high luminosity LHC programme. The brief discussion therefore focuses on the importance of high precision PDF and $α_s$ determinations for the physics beyond the Standard Model (G…
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The present note relies on the recently published conceptual design report of the LHeC and extends the first contribution to the European strategy debate in emphasising the role of the LHeC to complement and complete the high luminosity LHC programme. The brief discussion therefore focuses on the importance of high precision PDF and $α_s$ determinations for the physics beyond the Standard Model (GUTs, SUSY, Higgs). Emphasis is also given to the importance of high parton density phenomena in nuclei and their relevance to the heavy ion physics programme at the LHC.
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Submitted 9 January, 2013; v1 submitted 21 November, 2012;
originally announced November 2012.
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DIS2011 Heavy Flavours Session Summary (WG5)
Authors:
Olaf Behnke,
Alan Dion,
Fredrick Olness
Abstract:
We summarize the presentations of the Heavy Flavours working group for the 2011 DIS Workshop. This session contained presentations on theoretical methods and experimental measurements of heavy quark production, and the impact on recent experimental results from HERA, RHIC, Tevatron, and LHC.
We summarize the presentations of the Heavy Flavours working group for the 2011 DIS Workshop. This session contained presentations on theoretical methods and experimental measurements of heavy quark production, and the impact on recent experimental results from HERA, RHIC, Tevatron, and LHC.
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Submitted 5 February, 2012; v1 submitted 30 January, 2012;
originally announced January 2012.
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What HERA may provide ?
Authors:
Hannes Jung,
Albert De Roeck,
Jochen Bartels,
Olaf Behnke,
Johannes Blumlein,
Stanley Brodsky,
Amanda Cooper-Sarkar,
Michal Deak,
Robin Devenish,
Markus Diehl,
Thomas Gehrmann,
Guenter Grindhammer,
Gosta Gustafson,
Valery Khoze,
Albert Knutsson,
Max Klein,
Frank Krauss,
Krzysztof Kutak,
Eric Laenen,
Leif Lonnblad,
Leszek Motyka,
Paul R. Newman,
Fred Olness,
Daniel Pitzl,
Marta Ruspa
, et al. (4 additional authors not shown)
Abstract:
More than 100 people participated in a discussion session at the DIS08 workshop on the topic What HERA may provide. A summary of the discussion with a structured outlook and list of desirable measurements and theory calculations is given.
More than 100 people participated in a discussion session at the DIS08 workshop on the topic What HERA may provide. A summary of the discussion with a structured outlook and list of desirable measurements and theory calculations is given.
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Submitted 4 September, 2008; v1 submitted 3 September, 2008;
originally announced September 2008.
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Heavy Quarks: Summary Report
Authors:
J. Baines,
S. P. Baranov,
O. Behnke,
J. Bracinik,
M. Cacciari,
M. Corradi,
A. Dainese,
S. Diglio,
K. J. Eskola,
T. O. Eynck,
A. Geiser,
G. Grindhammer,
H. Jung,
B. A. Kniehl,
V. J. Kolhinen,
S. Kretzer,
K. Kutak,
E. Laenen,
Th. Lagouri,
A. V. Lipatov,
F. Maltoni,
A. D. Martin,
A. Meyer,
A. Morsch,
L. Motyka
, et al. (16 additional authors not shown)
Abstract:
The present status of the heavy-quark production theory is critically reviewed in the first contribution. The second contribution summarises the present heavy flavour data from HERA and gives an outlook of what can be expected from HERA-II. The potential of the LHC experiments for charm and beauty physics is reviewed in the 3rd contribution. Then the relevance of saturation and small-x effects t…
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The present status of the heavy-quark production theory is critically reviewed in the first contribution. The second contribution summarises the present heavy flavour data from HERA and gives an outlook of what can be expected from HERA-II. The potential of the LHC experiments for charm and beauty physics is reviewed in the 3rd contribution. Then the relevance of saturation and small-x effects to heavy quark production at HERA and at the LHC are discussed. The non-perturbative aspects of heavy-quark fragmentation and their relevance to HERA and LHC are discussed in the next contribution. Finally, a comparison of different theoretical predictions for HERA and LHC based on different approaches is presented.
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Submitted 19 March, 2007; v1 submitted 27 March, 2006;
originally announced January 2006.
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HERA and the LHC - A workshop on the implications of HERA for LHC physics: Proceedings - Part B
Authors:
S. Alekhin,
G. Altarelli,
N. Amapane,
J. Andersen,
V. Andreev,
M. Arneodo,
V. Avati,
J. Baines,
R. D. Ball,
A. Banfi,
S. P. Baranov,
J. Bartels,
O. Behnke,
R. Bellan,
J. Blumlein,
H. Bottcher,
S. Bolognesi,
M. Boonekamp,
D. Bourilkov,
J. Bracinik,
A. Bruni,
G. Bruni,
A. Buckley,
A. Bunyatyan,
C. M. Buttar
, et al. (169 additional authors not shown)
Abstract:
The HERA electron--proton collider has collected 100 pb$^{-1}$ of data since its start-up in 1992, and recently moved into a high-luminosity operation mode, with upgraded detectors, aiming to increase the total integrated luminosity per experiment to more than 500 pb$^{-1}$. HERA has been a machine of excellence for the study of QCD and the structure of the proton. The Large Hadron Collider (LHC…
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The HERA electron--proton collider has collected 100 pb$^{-1}$ of data since its start-up in 1992, and recently moved into a high-luminosity operation mode, with upgraded detectors, aiming to increase the total integrated luminosity per experiment to more than 500 pb$^{-1}$. HERA has been a machine of excellence for the study of QCD and the structure of the proton. The Large Hadron Collider (LHC), which will collide protons with a centre-of-mass energy of 14 TeV, will be completed at CERN in 2007. The main mission of the LHC is to discover and study the mechanisms of electroweak symmetry breaking, possibly via the discovery of the Higgs particle, and search for new physics in the TeV energy scale, such as supersymmetry or extra dimensions. Besides these goals, the LHC will also make a substantial number of precision measurements and will offer a new regime to study the strong force via perturbative QCD processes and diffraction. For the full LHC physics programme a good understanding of QCD phenomena and the structure function of the proton is essential. Therefore, in March 2004, a one-year-long workshop started to study the implications of HERA on LHC physics. This included proposing new measurements to be made at HERA, extracting the maximum information from the available data, and developing/improving the theoretical and experimental tools. This report summarizes the results achieved during this workshop.
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Submitted 19 March, 2007; v1 submitted 2 January, 2006;
originally announced January 2006.
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HERA and the LHC - A workshop on the implications of HERA for LHC physics: Proceedings - Part A
Authors:
S. Alekhin,
G. Altarelli,
N. Amapane,
J. Andersen,
V. Andreev,
M. Arneodo,
V. Avati,
J. Baines,
R. D. Ball,
A. Banfi,
S. P. Baranov,
J. Bartels,
O. Behnke,
R. Bellan,
J. Blumlein,
H. Bottcher,
S. Bolognesi,
M. Boonekamp,
D. Bourilkov,
J. Bracinik,
A. Bruni,
G. Bruni,
A. Buckley,
A. Bunyatyan,
C. M. Buttar
, et al. (169 additional authors not shown)
Abstract:
The HERA electron--proton collider has collected 100 pb$^{-1}$ of data since its start-up in 1992, and recently moved into a high-luminosity operation mode, with upgraded detectors, aiming to increase the total integrated luminosity per experiment to more than 500 pb$^{-1}$. HERA has been a machine of excellence for the study of QCD and the structure of the proton. The Large Hadron Collider (LHC…
▽ More
The HERA electron--proton collider has collected 100 pb$^{-1}$ of data since its start-up in 1992, and recently moved into a high-luminosity operation mode, with upgraded detectors, aiming to increase the total integrated luminosity per experiment to more than 500 pb$^{-1}$. HERA has been a machine of excellence for the study of QCD and the structure of the proton. The Large Hadron Collider (LHC), which will collide protons with a centre-of-mass energy of 14 TeV, will be completed at CERN in 2007. The main mission of the LHC is to discover and study the mechanisms of electroweak symmetry breaking, possibly via the discovery of the Higgs particle, and search for new physics in the TeV energy scale, such as supersymmetry or extra dimensions. Besides these goals, the LHC will also make a substantial number of precision measurements and will offer a new regime to study the strong force via perturbative QCD processes and diffraction. For the full LHC physics programme a good understanding of QCD phenomena and the structure function of the proton is essential. Therefore, in March 2004, a one-year-long workshop started to study the implications of HERA on LHC physics. This included proposing new measurements to be made at HERA, extracting the maximum information from the available data, and developing/improving the theoretical and experimental tools. This report summarizes the results achieved during this workshop.
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Submitted 31 January, 2006; v1 submitted 2 January, 2006;
originally announced January 2006.
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Heavy flavor production at HERA
Authors:
O. Behnke
Abstract:
Recent results of open charm and beauty production in electron proton scattering at HERA are presented. In photoproduction, the measured cross sections for charm exceed fixed order NLO QCD calculations. Experimental evidence supports the hypothesis that a significant fraction of photoproduction events with charm can be described by resolved photon processes, where the charm quark is a constituen…
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Recent results of open charm and beauty production in electron proton scattering at HERA are presented. In photoproduction, the measured cross sections for charm exceed fixed order NLO QCD calculations. Experimental evidence supports the hypothesis that a significant fraction of photoproduction events with charm can be described by resolved photon processes, where the charm quark is a constituent of the resolved photon. In deep inelastic scattering the NLO calculations give in general a fairly reasonable description of the observed charm cross sections. The measurements of the structure function $F_2^{cc}$ show that, at large photon virtualities and low x, the events with charm constitute a major part of the total ep cross section. The beauty cross sections both in photoproduction and in DIS exceed NLO predictions.
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Submitted 29 November, 2001;
originally announced November 2001.