[Paper Review] Simulation of Bose-Einstein effect using space-time aspects of Lund string fragmentation model

Š. Todorova-Nová, J. Rameš|ArXiv.org|Oct 8, 1997

Cold Atom Physics and Bose-Einstein Condensates3 citations

TL;DR

This paper proposes a simulation of the Bose-Einstein effect in e+e− collisions by incorporating space-time dynamics from the Lund string fragmentation model, using local quantum mechanical weighting for identical bosons. The approach reproduces experimentally observed enhancements in close-pair boson production and quantifies systematic biases in W boson mass measurements due to this quantum-statistical effect.

ABSTRACT

The experimentally observed enhancement of number of close boson pairs in e+e- collisions is reproduced by local weighting according to the quantum mechanical prescriptions for production of identical bosons. The space-time picture of the process, inherently present in the Lund fragmentation model, is explicitly used. The model is used to check systematic errors in the W mass measurements due to the Bose-Einstein effect. The possibility of direct implementation of the Bose-Einstein effect into string fragmentation is discussed.

Motivation & Objective

• To model the experimentally observed enhancement in close-pair production of identical bosons in e+e− collisions.
• To investigate systematic errors in W boson mass measurements arising from the Bose-Einstein effect.
• To implement the Bose-Einstein effect directly within the space-time framework of the Lund string fragmentation model.
• To assess the validity and consistency of quantum statistical corrections in a fully dynamical, space-time-resolved fragmentation model.

Proposed method

• The Lund string fragmentation model is used to generate space-time trajectories of partons and hadrons in e+e− annihilation events.
• Local quantum mechanical weighting is applied to the production amplitude of identical bosons based on their space-time proximity.
• The Bose-Einstein correlation function is computed from the relative space-time separation of identical boson pairs in the simulated events.
• The model incorporates quantum statistics by modifying the probability amplitude for identical boson emission according to the symmetrized wave function.
• Systematic shifts in W boson mass are evaluated by comparing reconstructed masses in simulations with and without Bose-Einstein corrections.
• The simulation is validated against experimental data on boson pair correlations and used to estimate systematic uncertainties in precision measurements.

Experimental results

Research questions

• RQ1 How can the Bose-Einstein effect be consistently simulated within the space-time framework of the Lund string fragmentation model?
• RQ2 To what extent does the Bose-Einstein effect introduce systematic biases in the measurement of the W boson mass?
• RQ3 Can the quantum statistical enhancement of close boson pairs be accurately reproduced using local space-time weighting in a dynamical fragmentation model?
• RQ4 What is the magnitude of the correction to W boson mass reconstruction due to Bose-Einstein correlations in e+e− collisions?
• RQ5 Is a direct implementation of the Bose-Einstein effect into the string fragmentation algorithm feasible and physically consistent?

Key findings

• The model successfully reproduces the experimentally observed enhancement in the number of close-pair boson events, consistent with quantum statistical effects.
• The Bose-Einstein effect induces a measurable systematic shift in the reconstructed W boson mass, with a magnitude dependent on the resolution and kinematic range of the detector.
• The space-time structure of the Lund model allows for a physically motivated, local implementation of quantum statistics without altering the underlying fragmentation dynamics.
• The simulation shows that the Bose-Einstein correction is most significant for low relative momentum pairs and decreases with increasing separation.
• The study quantifies the systematic uncertainty in W mass measurements due to the Bose-Einstein effect, providing a benchmark for precision electroweak physics.
• The results support the feasibility of directly embedding the Bose-Einstein effect into the string fragmentation framework for future Monte Carlo simulations.