How to create another html.tpl.php file for logged in users?
Implement hook_preprocess_html() in your theme (or module, both are equally valid) like so:

function MYTHEME_preprocess_html(&amp;$vars) {
  // Determine if the user is auth'd
  if (user_is_logged_in()) {
    // Add a theme hook suggestion.
    $vars['theme_hook_suggestions'][] = 'html__auth';
  }
}


Then add a html--auth.tpl.php file to your theme, clear the caches, and you should be good to go.