One thing most people dont realize is that both modern Judaism and Christianity are sister sects and daughter religions of 2nd temple Judaism the Judaism centered around the 2nd temple (completed by Herod) Christianity along with Modern Judaism are sister first century religions.
Modern Judaism dates from 70 AD with the council of Jamnia and more importantly with Rabbi Ben Zakkai. Rabbi Yohanan Ben Zakkai, following in the footsteps of Gamaliel and Hilal and other Pharisee teachers (rabbis) emphasized the Oral Torah and replaced the animal sacrifices with readings and study.
Modern Judaism is derived from the Pharisaical sect (and I dont mean that in a denigrating sense as pharisee sometimes is used, I mean in the purely historical sense) Jews of today are Modern Jews.
Now the Samaritans in particular
are
They still exist in Israel
there have been many genetic studies of the Samaritans, both to uncover their origins and to understand how they have survived so many generations of isolation. One such study by Peidong Shen and colleagues in the Journal Human Mutation has used both mitochondrial DNA and Y-chromosome DNA of modern-day Samaritans to discover their origins and genetic relationship to Near Eastern Jews. Their results are fascinating.
The mitochondrial DNA results, which show maternal history (i.e. your mothers mothers mother, etc.), reveal no major difference between the Samaritans, Jews, or Palestinians in the Levant who were also sampled. These three groups have relatively similar maternal genetic histories. However, the story of the Y-chromosome, which shows paternal history (i.e. your fathers fathers father) is quite different. Indeed, not only are the Y-chromosomes of the Jews and Samaritans more similar to each other than either is to the Palestinians, the Y-chromosomes of the Samaritans show striking similarities to a very specific Y-chromosome most often associated with Jewish men. Although the Samaritan type is slightly different from the Jewish type, it is clear that the two share a common ancestor, probably within the last few thousand years.
They hold to the Samaritan Pentateuch, reject the Oral Torah and the prophets
I would also add that the Samaritans helped the Jews during the Jewish-Roman wars. But after the Bar Kochkba revolt, the Samaritans themselves had their own revolts against the Romans and those were crushed as well.