How to align breve rests to the middle of a bar

Question

I have the following code in Lilypond:

\new ChoirStaff <<
 \new Staff <<
  \new Voice \relative a' {
    \time 4/2
    r\breve
   }
  \new Voice = "high" \relative d' {
    e1\rest d
  }
 >>
>>

This is what I'm trying to transcribe:

What I'm actually getting is this:

As you can see, the breve rest is clearly not at the middle of the bar (as shown in the first image), but it's on the far left (as shown in the second image). I want the breve rest to be aligned to the middle of the bar. How do I achieve this?

(Please ignore the time signature)

Answer 1

A whole-measure rest is written with R, not with r. Writing R\breve will take care of the centering.