Anonymous users cannot view the Search center box embedded in the theme. How can you make this search box available to them?
To enable this functionality, use these steps:
1. Log in to the portal using an administrative ID.
2. Go to Administration > Portlet Management > Portlets and add anonymous user role to Search Center portlet
3. Go to Administration > Manage Pages and add anonymous user role to the Search center page.
Note: This change does not automatically make all search scopes viewable to anonymous users, To make the scopes viewable by anonymous user, you must make it "Visible to Anonymous user" through the Manage search portlet.