qlat_scripts.v1.params_meas — Physical Measurement Parameters

Source: qlat/qlat_scripts/v1/params_meas.py

Note: Update this document when updating the source file.

Outline

1. Overview

2. Lattice Spacing

3. Meson Masses

4. Renormalization Constants (Vector/ Axial)

5. Residual Mass

6. Quark Masses

7. Mass Renormalization Factors

8. Examples

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Overview

This module defines physical measurement parameters for each ensemble used in continuum-limit extrapolations and physical-unit conversions. All values are set via set_param from rbc_ukqcd_params and accessed at runtime via get_param.

The parameters include:

• Inverse lattice spacing a_inv_gev for converting lattice quantities to GeV

• Meson masses (m_pi, m_kk) in lattice units

• Renormalization constants (zz_vv, zz_aa) for vector and axial currents

• Residual mass m_res for domain-wall fermions

• Light and heavy quark masses (m_l, m_h)

• Mass renormalization factors (zz_m_l, zz_m_h) for converting to MSbar scheme

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Lattice Spacing

Tag: a_inv_gev

Inverse lattice spacing in GeV, used to convert lattice-scale quantities to physical units.

Ensemble	a_inv_gev (GeV)
test-4nt16	1.0
24D, 32D, 48D	1.023
48I	1.730
64I, 64I-pq	2.359
32IfineH	3.148

---

Meson Masses

m_pi

Pion mass in lattice units.

Ensemble	m_pi
test-4nt16	0.2
24D, 32D, 48D	0.13975
48I	0.08049
32IfineH	0.11790

m_kk

Kaon mass in lattice units.

Ensemble	m_kk
test-4nt16	0.4
24D, 32D, 48D	0.504154
48I	0.28853
32IfineH	0.17720

---

Renormalization Constants

zz_vv

Vector current renormalization factor.

Ensemble	zz_vv
test-4nt16	0.7
24D, 32D, 48D	0.72672
48I	0.71076
64I, 64I-pq	0.74293
32IfineH	0.77700

zz_aa

Axial current renormalization factor.

Ensemble	zz_aa
test-4nt16	0.7
24D, 32D, 48D	0.73457
48I	0.71191
64I, 64I-pq	0.74341
32IfineH	0.77779

---

Residual Mass

Tag: m_res

Domain-wall fermion residual mass in lattice units.

Ensemble	m_res
test-4nt16	0.001
24D, 32D, 48D	0.0022824
48I	0.0006102
64I, 64I-pq	0.0003116
32IfineH	0.0006296

---

Quark Masses

m_l

Light quark mass in lattice units.

Ensemble	m_l
test-4nt8, test-4nt16	0.01
24D, 32D, 48D	0.00107
48I	0.00078
64I	0.000678
64I-pq	0.0006203
32IfineH	0.0047

m_h

Heavy (strange) quark mass in lattice units.

Ensemble	m_h
test-4nt8, test-4nt16	0.04
24D, 32D, 48D	0.0850
48I	0.0362
64I	0.02661
64I-pq	0.02539
32IfineH	0.0186

---

Mass Renormalization Factors

These convert bare lattice quark masses to the MSbar scheme at 3 GeV. Reference: Physical Review D 93, 074505 (2016).

zz_m_l

Light quark mass renormalization factor.

Ensemble	zz_m_l
64I, 64I-pq	2.997 / 2.198
48I	2.997 / 2.198 * 0.9715

zz_m_h

Heavy quark mass renormalization factor.

Ensemble	zz_m_h
64I, 64I-pq	81.64 / 60.62
48I	81.64 / 60.62 * 0.9628

zz_ss_l / zz_ss_h

Inverse mass renormalization factors (1 / zz_m_l and 1 / zz_m_h), computed from the above values.

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Examples

import qlat as q
q.begin_with_mpi([[1, 1, 1, 4]])
import qlat_scripts.v1 as qs

job_tag = "48I"

# Get inverse lattice spacing
a_inv = qs.get_param(job_tag, "a_inv_gev")
print(f"a^{{-1}} = {a_inv} GeV")

# Get pion mass in lattice units
m_pi = qs.get_param(job_tag, "m_pi")
# Convert to MeV
m_pi_mev = m_pi * a_inv * 1000
print(f"m_pi = {m_pi_mev:.1f} MeV")

# Get renormalization constants
zz_vv = qs.get_param(job_tag, "zz_vv")
zz_aa = qs.get_param(job_tag, "zz_aa")
print(f"Z_V = {zz_vv}, Z_A = {zz_aa}")

q.end_with_mpi()