Yes there are recent (and old) papers about this topic. All read the word from the 9th frame : Mecca/Medina/Kaba/Zem Zem... (yawn...)
 Altara  ..that letter/word .....
"9th frame" .....in the last three responses for me ..  mean 9th century Islamic story of  that Quranic word  
"muhajirun"..??    if it is, I am going to go to war  with you..
yes ..  muhajirun.. this UK girl  did not know/ does not know that  she is  a 
9th Century "muhajirun".What the hell  ....suddenly  i see some 20 posts.,    you  guys after drinking that Altara's  Zem Zem and  
 yawning  you guys are running race on high horses...  
well  let me read these links before i read posts..
1.
The Concept of Muhājirūn – and Its Potential Significance for the Piety of the Seventh-Century Qur'ānic Movement 2.  
Reflections on the Identity of the Arabian Conquerors  of the Seventh-Century Middle East 3. 
Fighting Words_ Religion, Violence, and the Interpretation of Sacred Textsthat 3rd  one has catchy heading..  i must read that..  good stuff good one.. and  damn   this guy Robert G. Hoyland  is very good story teller and great writer all the 25 pages of  his paper,  i would have said in 2 pages