Pandoc CJK & Greek MWE's Greek alphabet spacing too wide

Question

Background

I'm preparing a series of simple document templates on my personal site. To allow readers who have never used pandoc to see the visual output, I added some  <object class="responsive-embed"> to allow visual output display of the  PDF,  DOCX and  HTML from  Visual Studio Code plugin vscode-pandoc.

Problem

Thanks to pandoc does not recognize Chinese characters, I know that setting CJKmainfont allows pandoc to render CJK characters. However, it breaks the existing greek alphabets in the  output PDF.

Click the above screenshot to view  my page.

Method

The above sample documents are produced on another device. To let you see the undesirable visual output, I've prepared two MWEs.

group	target	control
Markdown source file name	cjk_article.md	article.md
Greek alphabets in file content	✓	✓
CJK characters in file content	✓	✗
mainfont	Times New Roman	Times New Roman
CJKmainfont	Noto Sans CJK SC	absent
CJK characters rendered	✓	✗
Greek alphabet spacing	✗	✓

I've chosen standalone instead of article for documentclass in order to produce PDF files that will be converted to PNG with pdftoppm, so that the steps and output are reproducible.

$ diff -u {,cjk_}article.md
--- article.md  2023-04-08 12:59:46.415084100 +0200
+++ cjk_article.md      2023-04-08 13:02:34.029625600 +0200
@@ -1,6 +1,7 @@
 ---
 documentclass: standalone
 mainfont: Times New Roman
+CJKmainfont: Noto Sans CJK SC
 ---
-Section Ωαβ.  Lôrém ipsùm dolor sit amet.
+Section Ωαβ.  Lôrém 繁體 ipsùm 简体 dolor こんにちは sit 조선글 amet.

During the compilation, I hadn't installed the dependencies, so MikTeX's on-the-fly installation was invoked for the following pakcages:

• xeCJK
• luatexja-fontspec.sty
• everyhook.sty
• svn-prov.sty
• UniJIS2004-UTF32-H
• HaranoAjiMincho-Regular.otf

I clicked "Install" so as to install the missing packages. The system complained about the missing font "NotoSansCJKSC", which I immediately installed.

$ find -path './*article.md' -print0 | \
> while IFS= read -r -d '' file; do
> pandoc --pdf-engine=lualatex $file -o ${file%md}pdf
> done
Error producing PDF.
! Package fontspec Error: The font "NotoSansCJKSC" cannot be found.
For immediate help type H <return>.
 ...
l.27   \fi

In my MWE, I'm using Noto Sans CJK SC instead of Noto Sans CJK TC in an answer for the linked TeX.SE question due to the name of the highlighted LaTeX package in the above screenshot.

After that, I repeated the above command, and the error message was gone. To produce observable results (to be included in the next section), I used pdftoppm (shipped with my MikTeX's installation).

$ !find
find -path './*article.md' -print0 | while IFS= read -r -d '' file; do pandoc --
pdf-engine=lualatex $file -o ${file%md}pdf; done
$ find -name '*article.pdf' -exec sh -c \
> 'f="{}"; pdftoppm -png -r 450 "$f" "${f%.*}" 2>/dev/null' \;
$ which pdftoppm
/c/Users/sere/AppData/Local/Programs/MiKTeX/miktex/bin/x64/pdftoppm

Remarks: thanks to this helpful one-liner for {} placeholder manipulation on Unix.SE. I suppressed the following warning message with 2>/dev/null.

MiKTeX requires Windows 10 (or greater): https://miktex.org/announcement/legacy-windows-deprecation

Results

Here're the output PNG for

• target group (✓ CJK)

  

• control group (✗ CJK)

  

To view pdftoppm -png's output in their original dimensions, I suggest clicking on these images to view their in a separate tab.

Question

How can I get the correct spacing between the greek alphabets (illustrated in the screenshot for the control group's output) with CJK characters (shown in the screenshot for the target group's output)?

Remarks: the above screenshot is made with MS Paint.

Answer 1

Thanks to the adopted answer of How do I use accented latin letters + russian + japanese in the same document? (mentioned by @JavierBezos in the comments), I've found the line that resolves this problem.

\ltjsetparameter{jacharrange={-2}}

pandoc provides the header-includes variable in which I can include this line of code.

Regarding the lines

\usepackage{iftex}
\usepackage{fontspec}
\defaultfontfeatures{Ligatures={TeX}}

I don't include them in that pandoc variable because it's already there in pandoc's default template, which loads the LaTeX package iftex.

The configurations for sansfont and monofont aren't the main focus of this problem. I've found that these variables are redundant in the following MWE.

babel-lang: english
babel-otherlangs: chinese, japanese, korean, greek 

Including and/or excluding these two lines won't affect the final result. pandoc's user manual provides more detailed info about the lang and babelfonts variable.

MWE:

---
documentclass: standalone
mainfont: Times New Roman
CJKmainfont: Noto Sans CJK SC
header-includes: |
  \ltjsetparameter{jacharrange={-2}}
---
Section Ωαβ.  Lôrém 繁體 ipsùm 简体 dolor こんにちは sit 조선글 amet.

Output: