Novak, Helga M.

Brandt, Marion

doi:10.1007/978-3-476-03702-2_271

Cited by 3 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ECEARTH model, which was developed as a part of Europe-wide consortium, is a recent earth system model which builds on model technology from the European Centre for Medium Range Weather Forecasting (ECMWF). For a detailed model description, the reader is referred to Brandt (2010).…”

Section: Regional Climate Modelsmentioning

confidence: 99%

Assessing the importance of spatio‐temporal RCM resolution when estimating sub‐daily extreme precipitation under current and future climate conditions

Pinya

Luchner

Onof

et al. 2016

Intl Journal of Climatology

View full text Add to dashboard Cite

Overall, the results from this study show the influence of the spatial resolution on the precipitation 1 outputs from RCMs. The biases of the RCM simulations increase and the projected changes 2 decrease for decreasing spatial resolution of the simulations. This points towards the need for high 3 spatial and temporal resolution RCMs to obtain reliable information on changes in sub-daily 4 extreme precipitation. 5

show abstract

Section: Regional Climate Modelsmentioning

confidence: 99%

Assessing the importance of spatio‐temporal RCM resolution when estimating sub‐daily extreme precipitation under current and future climate conditions

Pinya

Luchner

Onof

et al. 2016

Intl Journal of Climatology

View full text Add to dashboard Cite

show abstract

“…In the absence of sufficiently detailed experimental data from e + e − collisions, they are typically modeled on vector meson fragmentation [25]. As an alternative, it has been proposed to use slightly virtual photons decaying into low-mass lepton pairs, as these do not have fragmentation contributions and need not be isolated experimentally [26][27][28].…”

mentioning

confidence: 99%

How robust is a thermal photon interpretation of the ALICE low-p T data?

Klasen

Klein-Bösing

König

et al. 2013

J. High Energ. Phys.

View full text Add to dashboard Cite

We present a rigorous theoretical analysis of the ALICE measurement of low-p T direct-photon production in central lead-lead collisions at the LHC with a centre-of-mass energy of √ s N N = 2.76 TeV. Using NLO QCD, we compute the relative contributions to prompt-photon production from different initial and final states and the theoretical uncertainties coming from independent variations of the renormalisation and factorisation scales, the nuclear parton densities and the fragmentation functions. Based on different fits to the unsubtracted and prompt-photon subtracted ALICE data, we consistently find T = 304 ± 58 MeV and 309 ± 64 MeV for the effective temperature of the quark-gluon plasma (or hot medium) at p T ∈ [0.8; 2.2] GeV and p T ∈ [1.5; 3.5] GeV as well as a powerlaw (p −4 T ) behavior for p T > 4 GeV as predicted by QCD hard scattering.One of the goals of the physics program at the CERN Large Hadron Collider (LHC) is the study of deconfined, strongly interacting matter, which existed in the early universe and which can today be re-created and investigated in heavy-ion collisions. An important probe for this so-called quark-gluon plasma (QGP) are photons emitted from the deconfined partons before thermalisation, in the thermal bath, during expansion and cooling of the QGP, and finally from the thermal hadron gas. The transverse momentum distribution of these photons can be used to estimate the temperature of the system, although the exact interpretation is complicated by these different phases, the radial expansion, more generally the temporal evolution of phase space, and co-existing states of matter. Experimentally, an effective temperature is usually extracted from an exponential fit to the excess of directphoton production at low transverse momentum (p T ) above the expectation from vacuum production. In Ref. [1], the first observation of a low-p T direct-photon signal at the LHC has been reported by the ALICE collaboration. 1 There, an inverse slope parameter of T LHC = 304 ± 51 MeV has been extracted from an exponential fit to the photon spectrum in central (0-40%) lead-lead collisions at √ s N N = 2.76 TeV and low transverse momenta of p T ∈ [0.8; 2.2]GeV. The inverse slope parameter of this measurement is significantly higher than the one obtained previously by the PHENIX collaboration in 0-20% central gold-gold collisions with √ s N N = 200 GeV at RHIC, which resulted in T RHIC = 221 ± 19 ± 19 MeV [2]. The latter 1 In nuclear collision experiments, photons originating from meson decays are usually distinguished from direct photons. The latter are divided into thermal and non-thermal prompt (plus medium-induced) photons, and these again into photons produced directly in the hard collision and those coming from quark and gluon fragmentation. The double use of the word direct can sometimes lead to confusion.

show abstract

“…In this paper we advocate that these difficulties can be avoided by the use of virtual photons, which have neither decay nor fragmentation contributions and need not be isolated from hadronic spectators, since they give rise to an experimentally well identifiable lepton (electron or muon) pair. This idea was first introduced for unpolarised [12] and polarised [13] pp collisions, recently extended to weak boson production at very large transverse momenta [14], and is now applied to pA collisions. The transverse momentum spectra of massive vector bosons (J/Ψ, Υ and W/Z) produced in pA collisions have recently been studied elsewhere [15,16].…”

Section: Introductionmentioning

confidence: 99%

Nuclear parton density modifications from low-mass lepton pair production at the LHC

Brandt¹,

Klasen²,

König³

2014

Nuclear Physics A

View full text Add to dashboard Cite

In this article, we investigate the potential of low-mass lepton pair production in proton-ion collisions at the LHC to constrain nuclear modifications of parton densities. Similarly to prompt photon production, the transverse momentum spectrum is shown to be dominated by the QCD Compton process, but has virtually no fragmentation or isolation uncertainties. Depending on the orientation of the proton and ion beams and on the use of central or forward detector components, all interesting regions of nuclear effects (shadowing, antishadowing, isospin and EMC effects) can be probed. Ratios of cross sections allow to eliminate theoretical scale and bare-proton parton density errors as well as many experimental systematic uncertainties.

show abstract

Novak, Helga M.

Cited by 3 publications

References 0 publications

Assessing the importance of spatio‐temporal RCM resolution when estimating sub‐daily extreme precipitation under current and future climate conditions

Assessing the importance of spatio‐temporal RCM resolution when estimating sub‐daily extreme precipitation under current and future climate conditions

How robust is a thermal photon interpretation of the ALICE low-p T data?

Nuclear parton density modifications from low-mass lepton pair production at the LHC

Contact Info

Product

Resources

About