DDD: keep a link to an entity inside an aggregate root, for reporting only

Question

I'm refactoring a project using DDD, but am concerned about not making too many Entities their own Aggregate Root.

I have a Store, which has a list of ProductOptions and a list of Products. A ProductOption can be used by several Products. These entities seem to fit the Store aggregate pretty well.

Then I have an Order, which transiently uses a Product to build its OrderLines:

class Order {
    // ...
    public function addOrderLine(Product $product, $quantity) {
        $orderLine = new OrderLine($product, $quantity);
        $this->orderLines->add($orderLine);
    }
}

class OrderLine {
    // ...
    public function __construct(Product $product, $quantity) {
        $this->productName = $product->getName();
        $this->basePrice = $product->getPrice();
        $this->quantity = $quantity;
    }
}

Looks like for now, DDD rules as respected. But I'd like to add a requirement, that might break the rules of the aggregate: the Store owner will sometimes need to check statistics about the Orders which included a particular Product.

That means that basically, we would need to keep a reference to the Product in the OrderLine, but this would never be used by any method inside the entity. We would only use this information for reporting purposes, when querying the database; thus it would not be possible to "break" anything inside the Store aggregate because of this internal reference:

class OrderLine {
    // ...
    public function __construct(Product $product, $quantity) {
        $this->productName = $product->getName();
        $this->basePrice = $product->getPrice();
        $this->quantity = $quantity;

        // store this information, but don't use it in any method
        $this->product = $product;
    }
}

Does this simple requirement dictates that Product becomes an aggregate root? That would also cascade to the ProductOption becoming an aggregate root, as Product has a reference to it, thus resulting in two aggregates which have no meaning outside a Store, and will not need any Repository; looks weird to me.

Any comment is welcome!