ERROR when sending variable to php and capturing php array in jquery

I'm doing a car complete with jquery, php, sqlserver. I send a data to the file search-client.php with ajax but I can not get any results back and I can not see any kind of error in the browser.

JQuery code

$(document).ready(function(e) { 

        $("#rutb").keyup(function () {
                var value = $(this).val();
                $("#rutsf").val(value);
            });
        $("input#rutsf").rut()
          .on('rutValido', function(e, rut){
            alert("Su RUT sin DV es " + rut);
          });


          $("#rutb").change(function () {
              $("#rutb").each(function () {
                  busca = $(this).val();
                     $.ajax({
                         type:"GET",
                         url:"busca-cliente.php",
                         data:busca,
                         dataType:"html",
                         success: function(clientes){
                            alert("dato enviado");
                            ('#nombre').find('input').val(clientes.nom);
                            }
                  });

              });
          })




        });


        </script>

html on the same page

<form  method="get" id="buscador">
               <label for="rutb">Buscar cliente</label>
                <input name="rutb" type="text"  id="rutb" placeholder="Rut" 
/>
                <div class="errores" id="mrutb">El rut no es valido</div>
<!--             <button type="submit"   name="btn-buscar" id="btn-  buscar">Buscar</button> -->
        </form>

This form must be completed

<form method="post" id="ingresar" onSubmit="return Comprobar();">
<label for="nombre">Nombre</label>    
<input name="nombre" type="text" id="nombre" />
</form>

search-client.php

    <?php
    include_once "lib/conexion.php";


    $rutbuscador=$_GET['busca'];

      if(!empty($rutbuscador)){

        $con=conectar();
         $sqls = "SELECT    * FROM clientes WHERE (RutAux = '$rutbuscador')"; 

        $query= sqlsrv_query($con,$sqls);



        if(sqlsrv_has_rows($query)){

                while($fila=sqlsrv_fetch_array($query)){

                    $NOM=$fila[1];
                    $RUT=$fila[3];
                    $DIR=$fila[7];
                    $FON=$fila[8];
                    $EM=$fila[9];
                 $clientes[] = array('rut' =>$RUT,'nom' => $NOM,'tel' => $FON,'dir' => $DIR,'email' => $EM);




                }
                echo '<script>alert("$clientes[]"); </script>';
                echo $clientes;
            }else{
                ?> <div class="alert alert-warning" role="alert">No existen clientes con el rut : <?php echo $rutbuscador; ?></div><?php
            }
            }
    ?>