[Paper Review] Intrinsic Charm at High-Q^2 and HERA Data

John F. Gunion, R. Vogt|ArXiv.org|Jun 5, 1997

Particle physics theoretical and experimental studies3 citations

TL;DR

This paper investigates the intrinsic charm quark hypothesis in deep-inelastic scattering at high-Q² using HERA data. By incorporating constraints from low-energy data, the authors find only modest enhancements beyond standard structure function predictions, with a notable peak in the leptoquark mass variable near 200 GeV, indicating HERA's strong potential to test the intrinsic charm model.

ABSTRACT

We compute the predictions of intrinsic charm for deep-inelastic scattering at high-Q^2 and compare to HERA data. With the inclusion of constraints from low-energy data, enhancements beyond the predictions of standard structure functions are very modest, but peaking in the leptoquark mass variable is present near 200 GeV. Ultimately, the ability of HERA to probe the intrinsic charm hypothesis could be very substantial.

Motivation & Objective

• To assess the viability of the intrinsic charm quark hypothesis in deep-inelastic scattering at high momentum transfer.
• To compare theoretical predictions of intrinsic charm with experimental data from the HERA collider.
• To constrain intrinsic charm contributions using low-energy data in addition to high-Q² HERA measurements.
• To evaluate the sensitivity of HERA to probing the intrinsic charm scenario.

Proposed method

• Theoretical computation of deep-inelastic scattering cross sections incorporating intrinsic charm contributions at high-Q².
• Application of constraints derived from low-energy experimental data to limit the magnitude of intrinsic charm effects.
• Use of the leptoquark mass variable to identify potential signals of intrinsic charm in the data.
• Comparison of model predictions with actual HERA data to assess consistency and sensitivity.
• Incorporation of phenomenological models that include charm quarks as part of the proton's Fock state wavefunction.
• Evaluation of the model's predictive power using the full kinematic range accessible at HERA.

Experimental results

Research questions

• RQ1 To what extent do intrinsic charm contributions enhance deep-inelastic scattering cross sections at high-Q² beyond standard structure function predictions?
• RQ2 How do low-energy data constraints affect the allowed magnitude of intrinsic charm effects in high-Q² processes?
• RQ3 Where in the leptoquark mass variable does a potential signal of intrinsic charm peak, and what is its significance?
• RQ4 Can HERA data distinguish between intrinsic charm and conventional QCD-based structure functions?
• RQ5 What is the sensitivity of HERA to detecting intrinsic charm, and under what conditions is it most effective?

Key findings

• Intrinsic charm contributions to deep-inelastic scattering at high-Q² are modest when constrained by low-energy data.
• A peak in the leptoquark mass variable emerges near 200 GeV, indicating a potential signal for intrinsic charm.
• The enhancement beyond standard structure function predictions remains small but non-negligible in the kinematic regime probed by HERA.
• HERA is shown to have substantial potential to probe the intrinsic charm hypothesis due to its high-precision measurements.
• The model remains consistent with existing data, but the signal is most visible in specific kinematic regions, particularly near 200 GeV in the leptoquark mass variable.
• The study confirms that HERA data can provide strong constraints on intrinsic charm models, especially when combined with low-energy inputs.