[Paper Review] Inclusive D-Meson Production at the LHC

H. Spiesberger|arXiv (Cornell University)|May 31, 2012

Particle physics theoretical and experimental studies3 citations

TL;DR

This paper presents next-to-leading-order predictions for inclusive D-meson production at the LHC using the general-mass variable-flavor-number scheme (GM-VFNS), comparing theory with ALICE data at √s = 7 TeV. It demonstrates that proper scale choices in GM-VFNS can describe low-pT data, while large-rapidity measurements can constrain intrinsic charm models in the proton, with significant enhancements predicted for certain intrinsic charm parametrizations.

ABSTRACT

I present predictions for the inclusive production of D mesons at the CERN LHC in the general-mass variable-flavor-number scheme at next-to-leading order. Numerical results are compared to data where available, and uncertainties due to scale variations, parton distribution functions and charm mass are discussed. I point out that measurements at large rapidity have the potential to pin down models of intrinsic charm.

Motivation & Objective

• To provide precise next-to-leading-order predictions for inclusive D-meson production at the LHC using the GM-VFNS framework.
• To compare theoretical predictions with available ALICE data on transverse momentum and rapidity distributions.
• To assess theoretical uncertainties from scale variations, parton distribution functions (PDFs), and charm quark mass.
• To evaluate the potential of large-rapidity D-meson measurements to constrain models of intrinsic charm in the proton.

Proposed method

• Employing the general-mass variable-flavor-number scheme (GM-VFNS) at next-to-leading order to include resummation of large logarithms via DGLAP evolution of PDFs and fragmentation functions (FFs).
• Using CTEQ6.6 PDFs and FFs from Ref. [10] for the GM-VFNS calculation, with scale variations via ξi parameters to estimate theoretical uncertainties.
• Comparing GM-VFNS predictions with fixed-flavor number scheme (FFNS) results, particularly at low pT where FFNS performs better.
• Applying different PDF sets (CT10, MSTW08-NLO, NNPDF 2.1, HERAPDF 1.5) to assess PDF-related uncertainties in the cross section predictions.
• Incorporating intrinsic charm models from CTEQ6.6, including BHPS and high-strength sea-like charm components, to estimate rapidity-dependent enhancements in D-meson production.
• Normalizing all cross sections to the GM-VFNS prediction with ξi = 1 and varying scale parameters to explore controlled fading of heavy-quark contributions at low pT.

Experimental results

Research questions

• RQ1 How well do GM-VFNS predictions describe ALICE data on D0-meson transverse momentum distributions at √s = 7 TeV?
• RQ2 To what extent do scale variations and PDF uncertainties affect the theoretical predictions for D-meson production?
• RQ3 Can the choice of factorization and renormalization scale parameters in GM-VFNS improve agreement with data at low pT, where FFNS is traditionally preferred?
• RQ4 What is the sensitivity of D-meson production at large rapidity to models of intrinsic charm in the proton?
• RQ5 How do different PDF sets and charm quark masses influence the predicted cross sections, particularly at low pT?

Key findings

• The GM-VFNS prediction with ξi = 1 overestimates data at pT < 5 GeV, where the FFNS performs better, indicating a need for scale tuning in the GM-VFNS at low pT.
• With optimized scale parameters (e.g., ξI = ξF = 0.8, ξR = 1), GM-VFNS predictions can be brought into agreement with ALICE data across the full pT range, including low pT.
• Scale uncertainties are smaller in GM-VFNS than in FFNS, supporting its use at high pT where large logarithms are resummed.
• Different PDF sets (CT10, MSTW08-NLO, NNPDF 2.1, HERAPDF 1.5) yield consistent predictions within experimental uncertainties, with no strong preference for any single set.
• A residual dependence on the charm quark mass m_c persists at low pT due to inconsistent m_c values in PDF and FF fits, with m_c = 1.5 GeV used in this work differing from 1.3–1.4 GeV in some PDF sets.
• Theoretical predictions for intrinsic charm models (BHPS and high-strength sea-like) show significant enhancements in D-meson production at large rapidity, increasing with pT in the BHPS model, suggesting LHCb data can constrain these models.