child.js

var spawn = require('child_process').spawn;

var child = spawn('node', ['child.js', 'arg2'], {
 cwd: process.cwd(),
 env: process.env,
 detached: false,
 stdio: [ 'ignore', 'ignore', 'ignore', 'ipc' ]
})
.on('message', function (m) {
  // console.log('message', m);
  // child.disconnect();
  // child.unref();
})
.on('exit', console.error);

setInterval(function () {
  console.log('args', process.argv);
  process.send && process.send({ message: 'what' });
}, 1000);

parent.js

var spawn = require('child_process').spawn;

var child = spawn('node', ['child.js', 'arg1'], {
 cwd: process.cwd(),
 env: process.env,
 detached: true,
 stdio: [ 'ignore', 'ignore', 'ignore', 'ipc' ]
})
.on('message', function (m) {
  console.log('message', m);
  // child.disconnect();
  // child.unref();
})
.on('exit', console.error)

setInterval(function () { }, 2000);

spawn.js

var child = spawn('cmd.exe', [ '/C', 'start', '/B', process.execPath, 'child.js', 'arg1' ], {
 cwd: process.cwd(),
 env: process.env,
 detached: false,
 windowsVerbatimArguments: true,
 stdio: ['ignore', 'ignore', 'ignore']
})
.on('exit', console.error);