The most important superpower arms race may not be in things that bristle and roar and go boom in the night. Instead, the battle to deter - or, if necessary, beat - a potential adversary increasingly is being fought by men and women in white smocks bent over microscopes or peering at computer screens.
More and more, it is this technological race that determines the US/Soviet military balance. It is behind a Pentagon research and development (R&D) budget that has nearly doubled since President Reagan took office, as well as a systems of Soviet research institutes that has expanded twofold to more than 3,000 since 1960.
It is the main reason the military now accounts for an estimated half of all R&D in the Soviet Union and 30 percent in the United States.
And it is behind the recent crackdown on the export of technology to Warsaw Pact countries from the West and attempts by the US Defense Department to control even unclassified scientific data that may have military value.
According to the Pentagon, the US is still ahead of the USSR in 15 of the 20 most important basic technology areas related to military capability, with the two countries even in the other five (see chart). But of those 15 in which the US excels, it is losing its advantage in 7. And in weapons already deployed, the technological balance is more equal - with the Soviets ahead in several.
The US has a certain margin of technological superiority, ''But we can't take our lead for granted,'' Richard DeLauer, undersecretary of defense for research and engineering, told Congress recently. ''The Soviet Union is making a determined and, in many cases, successful effort to reduce or overcome our technological lead.''
In recent years, the Soviet Union has fielded new systems that rival those held by the US military. For example, the newest Soviet tactical aircraft now have ''look-down/shoot-down'' radar that threatens relatively slow-moving US cruise missiles. This is one reason that the Air Force has cut back its planned acquisition of air-launched cruise missiles in favor of such missiles incorporating ''stealth'' capabilites to hide from Soviet radar.
Plans for the new US ''midgetman'' mobile intercontinental ballistic missile include a maneuverable warhead that (the Pentagon hopes) will be able to dodge Soviet defense systems. President Reagan's ''Star Wars'' call for new US ballistic missile defenses is in response to the current Soviet lead in numbers of accurate intercontinental missile warheads. The US Navy is pressing its advantage in antisubmarine warfare to offset a much larger Soviet sub fleet.
In all of these areas, success or failure depends on taking advantage of the US lead in computers, telecommunications, and sensors. But officials worry that the Soviet Union may be closing the technological gap, largely through help from the West.
''With the increasing number of espionage cases targeted against our high-technology firms and clandestine commercial acquisition of advanced systems publicly disclosed last year, the Soviet effort to acquire Western technology has not slackened,'' Rear Adm. John Butts, director of naval intelligence, reported to the House Armed Services Committee last week.
Rep. Jim Courter (R) of New Jersey, a member of this committee and chairman of the Military Reform Caucus in Congress, says, ''The modes of transfer include open literature, seminars, East-West trade, and espionage.''
Representative Courter is one of many lawmakers favoring stricter controls on US exports through changes in the Export Administration Act. At the moment, House and Senate are caught up in this debate, which sees many US scientists, academicians, and business officials concerned about an undue clampdown on the flow of commerce and scientific data.
The Pentagon's Dr. DeLauer and other officials note that technology alone does not measure military capability. As Israel found out in its 1982 rout of the Syrian Air Forces, the training, tactics, and quality of officers and enlisted personnel can often make the difference.
And officials note that the Soviet research and development system does have serious problems, some related to a lack of competition in its economic system - inefficient use of Soviet engineering manpower, for instance.
Still, says the Pentagon's research chief, the US hope is that ''by exploiting a qualitative edge in weapon system capabilities, we can help offset our quantitative disadvantage and reduce the risk of war.'' US-SOVIET TECHNOLOGY RACE Relative standing in 20 areas of basic technology that most affect defense US superior 1. Computers and software (lead growing) 2. Electro-optical sensors (lead slipping) 3. Guidance and navigation (lead slipping) 4. Life sciences (human factors and genetic engineering) (lead holding) 5. Material (lightweight, high strength, high temperature) (lead slipping) 6. Microelectronic materials and integrated-circuit manufacturing (lead slipping) 7. Optics (lead slipping) 8. Propulsion (aerospace and ground vehicles) (lead slipping) 9. Radar sensor (lead slipping) 10. Robotics and machine intelligence (lead holding) 11. Signal processing (lead holding) 12. Signature reduction (stealth) (lead holding) 13. Submarine detection (lead hllding) 14. Telecommunications (includes fiber optics) (lead holding) 15. Production/manufacturing (includes automated control) (lead holding) US and USSR equal 16. Aerodynamics/fluid dynamics 17.Conventional warhead 18. Lasers 19. Nuclear warhead 20. Power sources Source: US Department of Denfense