My mother is recently deceased. My siblings want just a Mass said for our recently deceased mother. Is there a Mass for the Deceased other than a funeral?
Yes, a Requiem Mass (Missa pro defunctis) can be said for the soul of a deceased person, and Requiem Masses needn't be accompanied by a funeral/burial.
A Mass that includes your mother via Intentions for the Mass may fit your needs.
One way to remember your mother in a Mass is to contact the local parish, or the parish where she passed away, and make a request that the intentions of the Mass include her by name. (Anecdote: we have done this a number of times in the past four years since the death of my father-in-law, in his home parish, most recently on the day before Thanksgiving this year.) You could also ask to have a private Mass for, celebrated with your family, but that requires coordination with a priest.
For the Intentions of this Mass ...
The practice of praying for various individuals in the faith community is supported by a requirement from Canon Law.
Whenever a priest celebrates Mass, he has at least two intentions. The first intention is to celebrate the Mass according to what the Church does. The second is to apply the grace of that Mass towards a specific need, whether it be a person(s), living or dead, baptized or not, or a special need. Every parish pastor is required, by Canon Law, to offer at least one Mass on Sunday for the needs and intentions of his parishioners (Can. 534 §1).
Based on our family experience, you should contact your mother's parish, or your local parish, and ask to have her included in the intentions of a Mass that you will attend.
Can. 534 §1. After a pastor has taken possession of his parish, he is obliged to apply a Mass for the people entrusted to him on each Sunday and holy day of obligation in his diocese. If he is legitimately impeded from this celebration, however, he is to apply it on the same days through another or on other days himself.
§2. A pastor who has the care of several parishes is bound to apply only one Mass for the entire people entrusted to him on the days mentioned in §1.
§3. A pastor who has not satisfied the obligation mentioned in §§1 and 2 is to apply as soon as possible as many Masses for the people as he has omitted