Rotation tète Unity 3d

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerController : MonoBehaviour {

    public float jumpSpeed;
    public float speedOfPlayer;
    public float jetPackForce;
    public float Sensivity;

    private Rigidbody rb;
    private Vector3 rotate = Vector3.zero;

    // Use this for initialization
    void Start () {
        rb = GetComponent<Rigidbody> ();

    }

    // Update is called once per frame
    void Update () {
        //PLAYER MOVEMENTS

                            //LEFT
        if (Input.GetKey (KeyCode.A))
        {
            transform.Translate (Vector3.left * speedOfPlayer * Time.deltaTime);
        }
                            //RIGHT
        if (Input.GetKey (KeyCode.D))
        {
            transform.Translate (Vector3.right * speedOfPlayer * Time.deltaTime);
        }
                            //FORWARD
        if (Input.GetKey (KeyCode.W))
        {
            transform.Translate (Vector3.forward * speedOfPlayer * Time.deltaTime);
        }
                            //BACK
        if (Input.GetKey (KeyCode.S))
        {
            transform.Translate (Vector3.back * speedOfPlayer * Time.deltaTime);
        }
                            //JETPACK
        bool jetPackAct = Input.GetButton ("Jump");
        if (jetPackAct) {
            rb.AddForce (0, jetPackForce, 0);
        }

                            //LOOK AROUND
        float x_axis = Input.GetAxisRaw ("Mouse Y");
        float y_axis = Input.GetAxisRaw ("Mouse X");

        Vector3 lookAround_x = new Vector3 (0f, x_axis, 0f)* Sensivity;

        if (Input.GetButton ("Mouse X"))
            {
            transform.localRotation = lookAround_x;
        //transform.Rotate = (0, Input.GetAxis ("Mouse X") * Sensivity, 0);
        }
    }


}