A Leading Order $\nu\text{DIS}$ Monte Carlo Event Generator

nuDIS_Generator is a Monte Carlo event generator designed for Neutrino-Nucleon Deep Inelastic Scattering (DIS). It simulates neutrino fluxes originating from muon decays in flight, integrating physical cross-sections with LHAPDF sets and the VEGAS integration algorithm.

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🛠 Installation and Setup

To ensure all dependencies (like LHAPDF) are correctly installed, follow these steps:

1. Create the Conda Environment

Use the provided environment.yml file to create a dedicated environment with the necessary C++ and Python libraries:

conda env create -f environment.yml

2. Activate the Environment

conda activate nuDIS

3. Install Project Dependencies

Once the environment is active, install the project in "editable" mode. This will read the `pyproject.toml` file, install any remaining Python dependencies, and allow you to run the generator from anywhere:

pip install -e .

4. Download PDF Sets

You must download the LHAPDF sets specified in your configuration (e.g., NNPDF3.1):

lhapdf install PDF4LHC21_40

Notice that you can replace PDF4LHC21_40 with any other LHAPDF set of your choice. You have to update the pdf_set_name parameter in src/pdfs/pdf_set.py accordingly.

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🔬 Possible Processes

The following processes can be specified in the process field of the run card:

Neutrino on Proton (mu- in final state)

• d_p: d + neutrino → mu- + h
• s_p: s + neutrino → mu- + h
• b_p: b + neutrino → mu- + h
• ubar_p: u~ + neutrino → mu- + h
• cbar_p: c~ + neutrino → mu- + h

Antineutrino on Proton (mu+ in final state)

• dbar_p: d~ + antineutrino → mu+ + h
• sbar_p: s~ + antineutrino → mu+ + h
• bbar_p: b~ + antineutrino → mu+ + h
• u_p: u + antineutrino → mu+ + h
• c_p: c + antineutrino → mu+ + h

Neutrino on Neutron (mu- in final state)

• d_n: d + neutrino → mu- + h
• ubar_n: u~ + neutrino → mu- + h

Antineutrino on Neutron (mu+ in final state)

• dbar_n: d~ + antineutrino → mu+ + h
• u_n: u + antineutrino → mu+ + h

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⚙️ Run Card Configuration

The simulation is controlled via card/cross_section_card.dat or card/events_card.dat. The first file is used for cross-section calculations, while the second is for event generation.

Below is a description of the parameters:

Process and Beam

• process: The name of the process from the list above.
• E_muon: Energy of the parent muon beam in GeV.

PDF Settings

• replica: The PDF replica ID. Use 0 for the central member, or N for specific error variations.

Theoretical Cuts

• Q2_min_theory: Minimum momentum transfer squared ($Q^2$) allowed in the integration [GeV²].
• W2_min_theory: Minimum hadronic invariant mass squared ($W^2$) allowed [GeV²].

VEGAS Parameters

• vegas_iter: Number of adaptive iterations for the VEGAS algorithm.
• vegas_eval: Number of function evaluations per iteration.

Binning Configuration

• num_bins_x / Q2 / E: Number of bins for each observable.
• x_min_bin / x_max_bin: Range for Bjorken x.
• Q2_min_bin / Q2_max_bin: Range for $Q^2$ [GeV²].
• E_min_bin / E_max_bin: Range for the Neutrino Energy [GeV].
  • Note: If E_max_bin is set to -1, the generator automatically calculates the maximum kinematic limit based on the muon beam energy.

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💻 Usage

Run the generator by passing the path to your run card:

python events.py --card card/events_card.dat
python cross_section.py --card card/cross_section_card.dat